45 Cal.Rptr.3d 316 (2006) 38 Cal.4th 1177 137 P.3d 153

JOHN B., Petitioner,
v.
The SUPERIOR COURT of Los Angeles County, Respondent;
Bridget B., Real Party in Interest.

No. S128248.

Supreme Court of California.

July 3, 2006.

*318 Garrard & Davis, Donald A. Garrard, Santa Monica; and Eric S. Multhaup for Petitioner.

No appearance for Respondent.

Grassini & Wrinkle, Maryann P. Gallagher, Los Angeles, and Roland Wrinkle, Woodland Hills, for Real Party in Interest.

*317 BAXTER, J.

This is a sad case. Bridget B., the plaintiff in the underlying action and real party in interest herein, is infected with the human immunodeficiency virus (HIV), the probable causative agent of acquired immune deficiency syndrome (AIDS). So is her husband, petitioner herein and defendant in the underlying action, John B.

Bridget alleges that John became infected with HIV first, as a result of engaging in unprotected sex with multiple men before and during their marriage, and that he then knowingly or negligently transmitted the virus to her. John, who now has full-blown AIDS, alleges in his answer that Bridget infected him and offers as proof a negative HIV test conducted in connection with his application for life insurance on August 17, 2000, six weeks before Bridget discovered she was infected with HIV.

This factual scenario raises a number of interesting questions: What duty does an HIV-positive individual have to avoid transmitting the virus? What level of awareness should be required before a court imposes a duty of care on an HIV-positive individual to avoid transmission of the virus? What responsibility does the victim have to protect himself or herself against possible infection with the virus? And who infected whom with HIV here? However, this case comes to us at an early stage, before any discovery has been conducted. The issue here is simply the extent to which Bridget may inquire into John's medical records and sexual conduct in order to confirm or refute her allegations that John knowingly or negligently infected her with HIV.

The proposed discovery treads on important statutory and constitutional privacy rights. To decide what discovery should be permitted, we must balance Bridget's right to discover relevant evidence against John's right to privacy. After balancing these interests, the superior court overruled John's objections and authorized broad discovery into John's medical records as well as his sexual history over the past 10 years. The Court of Appeal granted John's petition for writ of mandate to the extent the discovery sought the identities of John's previous sexual partners and admissions concerning his "lifestyle," but otherwise denied relief.

We conclude that discovery should be further limited in light of John's negative HIV test on August 17, 2000, which restricts the window period of possible infection to the six months preceding the negative test. However, Bridget, on remand, may overcome this temporal limitation on discovery by offering some basis to question the accuracy or reliability of John's *319 negative HIV test. We therefore affirm in part and reverse in part the judgment of the Court of Appeal and remand the matter for further proceedings.

I. THE PLEADINGS

Bridget's complaint for damages alleges the following:

Plaintiff Bridget B. and defendant John B. met in September 1998 and began dating shortly thereafter. The couple became engaged in late 1999 and were married in July 2000. During this period, John represented to Bridget that he was healthy, disease-free, and monogamous. Indeed, it was John who insisted that the couple stop using condoms during intercourse. Based on John's representations, Bridget complied with his demand to engage in unprotected sex. In September 2000, however, Bridget began to suffer from exhaustion and high fevers.

On October 1, 2000, Bridget learned that she had tested positive for HIV. She was advised to undergo a second test and to have her husband tested as well. The second test confirmed that Bridget was HIV positive. John, too, was determined to be HIV positive. John's doctor told Bridget that she had "brought the HIV into the marriage." The doctor prescribed medications for John that made his viral load virtually undetectable. Bridget, on the other hand, was not offered treatment; she was informed that she had "had the illness for a long time." Bridget became depressed that she had infected her husband with this deadly disease.

In September 2001, John began telling others that Bridget had infected him with HIV. The next month, after defendant refused to continue his treatment, he became much sicker and developed sores on his face and scalp. Although he was diagnosed with AIDS, he refused all treatments and medications except those that treated the visible signs of the disease.

In November 2001, Bridget began to doubt that she had been the cause of defendant's infection. John responded by asking whether she was "accusing" him of bringing HIV into their lives and advised "it would not be healthy for their marriage to blame him." The following month, however, John admitted to Bridget that he had had sexual relations with men before their marriage. The complaint further alleges that John also engaged in sexual relations with men during their marriage and used the Internet to solicit these relationships.

The first cause of action (intentional infliction of emotional distress) alleges in material part that John knew he was HIV positive before he married Bridget and before he engaged in unprotected sexual relations with her, that he infected her with HIV knowingly and intentionally, and that he then falsely accused her of infecting him. It further alleges that Bridget was unaware that John had been unfaithful prior to and during their marriage, which put her at great risk for HIV, AIDS, syphilis, and other sexually transmitted diseases, and that she would not have engaged in unprotected sexual relations with him had she known of his infidelity.

The second cause of action (negligent infliction of emotional distress) alleges that John knew or had a reasonable belief that he had HIV, that he nonetheless engaged in unprotected sex with Bridget, and that his negligence caused her to become infected with HIV.

The third cause of action (fraud) alleges that John falsely represented that he did not have any communicable diseases, including HIV, AIDS, or syphilis; that Bridget engaged in unprotected sexual relations with John in reliance on those representations; and that John thereby infected her with HIV.

*320 The fourth cause of action (negligence) incorporates the foregoing allegations and alleges that John owed Bridget a duty of care to disclose the fact that he was HIV positive, that he breached this duty, and that he thereby infected her with HIV.

John's answer denied every allegation in the complaint and alleged instead that "[i]f either party transmitted the HIV virus to the other, it was Plaintiff who transmitted the virus to the Defendant." The answer also asserted Bridget's comparative fault as a defense in that she had "intimate sexual relations with Defendant without using condoms or any other form of protection against the HIV virus or other sexually transmitted diseases." In a declaration attached to his motion for summary judgment, John stated that he had been tested for HIV in connection with a life insurance application on August 17, 2000, and was found to be negative. John further alleged that he did not discover he was HIV positive until October 13, 2000.

II. DISCOVERY PROCEEDINGS

As relevant here, Bridget's pretrial discovery included the service of special interrogatories and requests for admission concerning John's sexual history and his awareness of his HIV infection. Bridget also subpoenaed John's medical and employment records. John objected to each and every special interrogatory and request for admission and also filed motions to quash the subpoenas duces tecum. After plaintiff filed motions to compel responses to the interrogatories and requests for admission, the parties stipulated to the appointment of a discovery referee to hear the pending discovery motions and to make nonbinding recommendations. The referee recommended that John's objections be overruled and his motions to quash be denied. The superior court adopted the referee's recommendations.

John filed the instant petition for writ of mandate. The Court of Appeal issued an order to show cause and granted the petition as to four interrogatories and two requests for admission, but otherwise denied relief in a published opinion. Because the issue before us concerns the permissible scope of discovery propounded by Bridget, we describe with particularity the discovery requests in controversy and John's objections to them below.

A. The Special Interrogatories

Bridget served special interrogatories that required John to state (1) the name, address, and telephone number of every man with whom he has had sexual relations in the last 10 years; (2) the date of his first sexual encounter with a man; (3) the date of his last sexual encounter with a man; (4) the name, address, and telephone number of every man with whom he has had unprotected sex in the last 10 years; (5) the date on which he first became aware he was HIV positive; (6) the date on which he first became aware he had AIDS; (7) the date on which he first told Bridget that he had engaged in unprotected sex with men; (8) the name, address, and telephone number of every HIV-positive man with whom he has had unprotected sex; (9) the name, address, and telephone number of every man who has AIDS and with whom he has had unprotected sex; (10) the number of sexual encounters with men he has had in the five years prior to his relationship with Bridget; (11) the date of his last sexual encounter with a man prior to the date of his engagement to Bridget; (12) the date of every sexual encounter he had with a man between his engagement to Bridget and the wedding; and (13) the number of sexual encounters he has had with men since he first met Bridget.

*321 John objected to each of these interrogatories as burdensome, oppressive, overly broad, and harassing, and claimed that they were an invasion of his right to privacy under the state and federal Constitutions. He also objected to selected interrogatories as violative of the physician-patient privilege (Evid.Code, § 990 et seq.) and Health and Safety Code section 120975. In his responses, John disclosed only that he first discovered he had tested positive for HIV on October 13, 2000.

The Court of Appeal granted John's petition for writ of mandate as to interrogatories Nos. 1, 4, 8, and 9, which sought the identities of his previous sexual partners, and denied relief as to the rest. Bridget had asserted a need to discover the identities of these sexual partners on the ground that John might have told these persons he had HIV but, as the Court of Appeal observed, she offered "nothing to support the suggestion that John may have disclosed his condition at an undisclosed time to an undisclosed person."

B. The Requests for Admission

Bridget requested John to admit that (1) he had had unprotected sexual relationships with multiple men in the 10 years prior to meeting Bridget; (2) he never told Bridget before they were married that he had had any sexual relationships with men; (3) he had AIDS prior to the time he first had unprotected sex with Bridget; (4) he knew he had AIDS prior to the time he first had unprotected sex with Bridget; (5) he transmitted AIDS to Bridget; (6) he transmitted HIV to Bridget; (7) he never told Bridget, prior to the time he had unprotected sex with her, that he had had unprotected sexual encounters with men; (8) he knew that his lifestyle prior to the time that he met Bridget put him at risk of acquiring HIV; (9) he never told Bridget, prior to having unprotected sex with her, about his lifestyle of having unprotected sex with men; (10) he continued to have unprotected sexual relationships with men after he was married; (11) prior to his marriage, he hid his sexual relations with men from Bridget; (12) he knew he had a history of having unprotected sexual relations with men that put him at risk of acquiring HIV at the time he accused Bridget of infecting him with HIV; (13) he has AIDS; (14) he knew he had AIDS before he married Bridget; and (15) he hid his sexual relations with men from Bridget before the wedding.

John objected to each of these requests as burdensome, oppressive, overly broad, and harassing, and claimed that they were an invasion of his right to privacy under the state and federal Constitutions. He also objected to selected requests as violative of Health and Safety Code section 120975.

The Court of Appeal granted John's petition for writ of mandate as to requests Nos. 8 and 9, which referred to his "lifestyle," but denied relief as to the rest. The Court of Appeal determined that the word "lifestyle" was vague and ambiguous and, to the extent it suggested a sexual orientation, impermissibly intruded into John's zone of sexual privacy.

C. The Subpoenas of Medical and Employment Records and the Results of HIV Tests

Bridget subpoenaed John's medical records, seeking the results of any HIV and AIDS tests, medical records concerning HIV and AIDS and treatment for those conditions, medical records concerning any and all sexually transmitted diseases since 1980, and medical records concerning any "treatment" he had received since 1980. Bridget also subpoenaed John's employment records from Universal Studios, including records "regarding his medical *322 leave and the reasons therefor" and "any disability he was suffering from."

John filed a motion to quash the subpoenas on the grounds that the subpoenas were not supported by affidavits or declarations as required by Code of Civil Procedure section 1985, subdivision (b) or by good cause; that the records were privileged from discovery under the right to privacy in the state and federal Constitutions; that the records were additionally privileged from discovery under Health and Safety Code section 120975 and Evidence Code sections 994 and 1014; and that the subpoenas constituted harassment.

The referee recommended the motions to quash be denied but limited the discoverable medical records relating to treatment since 1980 to "those regarding treatment received `for AIDS or HIV infection.'" The superior court adopted the referee's recommendation, and the Court of Appeal denied relief as to this part of the order.

III. DISCUSSION

John asserts a number of reasons for limiting discovery of his sexual history and HIV status, including his constitutional right to privacy, but we first determine whether the requested discovery comports with statutory requirements. (See Schnabel v. Superior Court (1993) 5 Cal.4th 704, 711, 21 Cal.Rptr.2d 200, 854 P.2d 1117; Vinson v. Superior Court (1987) 43 Cal.3d 833, 838, 239 Cal.Rptr. 292, 740 P.2d 404.) "`Under the discovery statutes, information is discoverable if it is unprivileged and is either relevant to the subject matter of the action or reasonably calculated to reveal admissible evidence.'" (Schnabel, supra, 5 Cal.4th at p. 711, 21 Cal.Rptr.2d 200, 854 P.2d 1117.) "Discovery may relate to the claim or defense of the party seeking discovery or of any other party to the action." (Code Civ. Proc., § 2017.010.) "In reviewing an order of a superior court granting discovery, we recognize at the threshold that `the discovery statutes vest a wide discretion in the trial court in granting or denying discovery' and `such exercise [of discretion] may only be disturbed when it can be said that there has been an abuse of discretion.'" (Pacific Tel. & Tel. Co. v. Superior Court (1970) 2 Cal.3d 161, 171, 84 Cal.Rptr. 718, 465 P.2d 854.)

The subject matter of this action concerns Bridget's allegation that John infected her with HIV. The gist of the four causes of action — intentional infliction of emotional distress, negligent infliction of emotional distress, fraud, and negligence — is that John represented to Bridget that he was monogamous and had no sexually transmitted diseases; that John made these representations to convince Bridget to engage in unprotected sex with him; that, contrary to these representations, John had not been monogamous and had knowledge, actual or constructive, that he was HIV positive; that John nonetheless had unprotected sex with Bridget without telling her that he was HIV positive; and that Bridget was unaware that John was HIV positive and had not been monogamous. In his defense, John denies infecting Bridget and asserts that if either party infected the other, Bridget infected him.

In light of these allegations, the special interrogatories and requests for admission at issue are within the statutory limits of discoverability. Bridget seeks to discover whether John has AIDS (request for admission No. 13); whether he infected her with HIV and AIDS (request for admission Nos. 5, 6); when John first became aware that he was HIV positive (special interrogatory No. 5); and when he first discovered that he had developed AIDS (special interrogatory No. 6; request for admission *323 Nos. 3, 4, 14). For her claims concerning infliction of emotional distress, Bridget asked John to admit that he knew his sexual behavior had put him at risk of contracting HIV at the time he accused her of infecting him. (Request for admission No. 12.) To help establish that she had been justifiably ignorant of John's HIV status, Bridget propounded discovery designed to show that John did not tell her he had previously engaged in unprotected sex with men. (Special interrogatory No. 7; request for admission Nos. 2, 7, 11, 15.) Finally, Bridget sought to establish that John had infected her (and not the other way around) by asking John to admit that he had engaged in unprotected sex with men prior to meeting her and during their courtship, engagement, and marriage and by inquiring into the dates and numbers of these encounters. (Special interrogatory Nos. 2, 3, 10-13; request for admission Nos. 1, 10.)

Having determined that the discovery requests authorized by the Court of Appeal meet the statutory standard of discoverability, we proceed to consider John's specific objections.

A. Whether Discovery Must Be Limited Because the Torts in the Complaint Require Proof That the Infected Individual Had Actual Knowledge of the Infection

John does not deny he would be liable if he had actual knowledge he was infected with HIV and failed to disclose that fact to Bridget. However, he vigorously denies that he can be held liable if the evidence shows only that he had constructive knowledge he was infected with HIV. He concludes, therefore, that discovery should be limited to those requests aimed at uncovering whether he had actual knowledge that he was infected with HIV. According to John, such knowledge can be established only by a positive HIV test from an accredited laboratory or a medical diagnosis of HIV or AIDS.

John's proposed limitation on discovery calls into question the scope of the torts alleged in the complaint, principally the fourth cause of action for negligent transmission of HIV. This court has not yet had occasion to consider the tort of negligent transmission of a sexually transmitted disease, but the tort is far from novel. Our sister jurisdictions have long imposed liability on individuals who have harmed others by transmitting communicable diseases. (See, e.g., Berner v. Caldwell (Ala. 1989) 543 So.2d 686, 688 ["For over a century, liability has been imposed on individuals who have transmitted communicable diseases that have harmed others"]; Crowell v. Crowell (1920) 180 N.C. 516, 105 S.E. 206, 208 ["it is a well-settled proposition of law that a person is liable if he negligently exposes another to a contagious or infectious disease"]; see generally 39 Am.Jur.2d (1999) Health, § 99, p. 549 ["The general principle is established that a person who negligently exposes another to an infectious or contagious disease, which such other thereby contracts, is liable in damages"].) In particular, courts throughout the United States have recognized a cause of action for the negligent transmission of sexually transmitted diseases. (E.g., McPherson v. McPherson (Me.1998) 712 A.2d 1043, 1045 [citing cases]; Hamblen v. Davidson (Tenn.Ct. App.2000) 50 S.W.3d 433, 438 ["all the jurisdictions which have considered the issue"]; Doe v. Johnson (W.D.Mich.1993) 817 F.Supp. 1382, 1389 [citing cases].) California appellate courts are in accord. (Doe v. Roe (1990) 218 Cal.App.3d 1538, 1543 & fn. 3, 267 Cal.Rptr. 564; Kathleen K. v. Robert B. (1984) 150 Cal.App.3d 992, 996-997, 198 Cal.Rptr. 273.) We agree with these courts that "[t]o be stricken with disease through another's negligence *324 is in legal contemplation as it often is in the seriousness of consequences, no different from being struck with an automobile through another's negligence." (Billo v. Allegheny Steel Co. (1937) 328 Pa. 97, 195 A. 110, 114.)

To prevail in an action for negligence, the plaintiff must demonstrate that the defendant owed a duty to the plaintiff, that the defendant breached that duty, and that the breach proximately caused the plaintiff's injuries. (Wiener v. Southcoast Childcare Centers, Inc. (2004) 32 Cal.4th 1138, 1145, 12 Cal.Rptr.3d 615, 88 P.3d 517.)

The existence of a legal duty is a question of law for the court. (Delgado v. Trax Bar & Grill (2005) 36 Cal.4th 224, 237, 30 Cal.Rptr.3d 145, 113 P.3d 1159.) "As this court has explained, `duty' is not an immutable fact of nature `"but only an expression of the sum total of those considerations of policy which lead the law to say that the particular plaintiff is entitled to protection."' [Citations.] In California, the general rule is that all persons have a duty `"to use ordinary care to prevent others being injured as the result of their conduct. . . ."' (Rowland v. Christian (1968) 69 Cal.2d 108, 112 [70 Cal.Rptr. 97, 443 P.2d 561] (citations omitted); Civ. Code, § 1714.)" (Ballard v. Uribe (1986) 41 Cal.3d 564, 572-573, fn. 6, 224 Cal.Rptr. 664, 715 P.2d 624.) Foreseeability of harm is a "`crucial factor'" in determining the existence and scope of that duty. (Delgado, supra, 36 Cal.4th at p. 237, 30 Cal. Rptr.3d 145, 113 P.3d 1159.)

John concedes that a person who actually knows he or she is infected with a sexually transmitted disease based on a test from an accredited laboratory or a medical diagnosis has a duty to use ordinary care to see that the disease is not transmitted to others. The foreseeability of harm in such a circumstance is manifest. John also concedes the viability of the tort of negligent transmission of HIV. In his view, though, a duty under this tort exists only when the actor has actual knowledge of being HIV positive; constructive knowledge of the infection is insufficient.

Tellingly, neither John nor our dissenting colleagues have identified a single jurisdiction that has limited liability for negligent transmission of HIV or other sexually transmitted diseases only to those who have actual knowledge they are infected. Our sister states instead impose liability when the actor has knowledge, actual or constructive, of a sexually transmitted disease. (Berner v. Caldwell, supra, 543 So.2d at pp. 689-690 & fn. 4 [applying this standard to the transmission of herpes and noting that the same duty could be imposed for other sexually transmitted diseases, including AIDS]; Meany v. Meany (La.1994) 639 So.2d 229, 236; McPherson v. McPherson, supra, 712 A.2d at p. 1046; Deuschle v. Jobe (Mo.Ct.App.2000) 30 S.W.3d 215, 219; M.M.D. v. B.L.G. (Minn.Ct.App.1991) 467 N.W.2d 645, 647 [liability for negligent transmission of herpes exists where boyfriend had history of genital sores but had not been diagnosed with herpes]; Mussivand v. David (1989) 45 Ohio St.3d 314, 544 N.E.2d 265, 270 ["We find the reasoning of these other jurisdictions persuasive"]; Plaza v. Estate of Wisser (App. Div.1995) 211 A.D.2d 111, 626 N.Y.S.2d 446, 451-452 [allegations of decedent's actual and constructive knowledge he was infected with HIV was sufficient to withstand motion to dismiss claims of fraud and negligence]; Hamblen v. Davidson, supra, 50 S.W.3d at p. 439 [noting that "the majority of states who have addressed the issue" extend liability to those with actual or constructive knowledge of the sexually transmitted disease]; Doe v. Johnson, supra, 817 F.Supp. at p. *325 1391 [liability for negligent transmission of HIV includes those who "knew s/he was suffering symptoms associated with the HIV virus . . . or . . . knew of a prior sex partner who was diagnosed as having the HIV virus"]; accord, 65 C.J.S. (2000) Negligence, § 171, p. 503.)

Extending liability to those who have constructive knowledge of the disease, as these jurisdictions have done, comports with general principles of negligence. Indeed, the "very concept of negligence presupposes that the actor either does foresee an unreasonable risk of injury, or could have foreseen it if he conducted himself as a reasonably prudent person." (3 Harper et al., The Law of Torts (2d ed.1986) § 16.5, p. 397; accord, Prosser & Keeton on Torts (5th ed.1984) § 32, pp. 182-185; Rest.2d Torts, §§ 289, 290; Nolte, The Spoliation Tort: An Approach to Underlying Principles (1994) 26 St. Mary's L.J. 351, 380 ["negligence law regularly utilizes the concept of constructive knowledge as the requisite notice"].) Because "`[a]ll persons are required to use ordinary care to prevent others being injured as a result of their conduct'" (Rowland v. Christian, supra, 69 Cal.2d at p. 112, 70 Cal.Rptr. 97, 443 P.2d 561), this court has repeatedly recognized a cause of action for negligence not only against those who have actual knowledge of unreasonable danger, but also against those who have constructive knowledge of it. (See, e.g., Ortega v. Kmart Corp. (2001) 26 Cal.4th 1200, 1210, 114 Cal.Rptr.2d 470, 36 P.3d 11; Toland v. Sunland Housing Group, Inc. (1998) 18 Cal.4th 253, 260, fn. 1, 74 Cal.Rptr.2d 878, 955 P.2d 504; Kentucky Fried Chicken of Cal., Inc. v. Superior Court (1997) 14 Cal.4th 814, 823, 59 Cal.Rptr.2d 756, 927 P.2d 1260; Garcia v. Superior Court (1990) 50 Cal.3d 728, 735, 268 Cal.Rptr. 779, 789 P.2d 960; Hasson v. Ford Motor Co. (1982) 32 Cal.3d 388, 407, 185 Cal.Rptr. 654, 650 P.2d 1171.) Neither John nor our dissenting colleagues have pointed to any indication that the Legislature intended a lesser duty to apply to HIV.

Moreover, limiting tort defendants to those who have actual knowledge they are infected with HIV would have perverse effects on the spread of the virus. If only those who have been tested are subject to suit, there may be "an incentive for some persons to avoid diagnosis and treatment in order to avoid knowledge of their own infection." (Gostin & Hodge, Piercing the Veil of Secrecy in HIV/AIDS and Other Sexually Transmitted Diseases: Theories of Privacy and Disclosure in Partner Notification (1998) Duke J. Gender L. & Poly. 9, 40.) Extending liability to those with constructive knowledge of the disease, on the other hand, "will provide at least a small incentive to others to use proper diagnostic techniques and to alter behavior and procedures so as to limit the likelihood of HIV transmission." (Hermann, Torts: Private Lawsuits about AIDS in AIDS and the Law: A Guide for the Public (Dalton & Yale AIDS Law Project edits., 1987) p. 172 (Hermann).) Justice Moreno offers no support for his view that tort liability would have no effect on human behavior in this context.

It must be noted, though, that "constructive knowledge," which means knowledge "that one using reasonable care or diligence should have, and therefore is attributed by law to a given person" (Black's Law Dict. (7th ed.1999) p. 876), encompasses a variety of mental states, ranging from one who is deliberately indifferent in the face of an unjustifiably high risk of harm (see Farmer v. Brennan (1994) 511 U.S. 825, 836-840, 114 S.Ct. 1970, 128 L.Ed.2d 811) to one who merely should know of a dangerous condition (see Ortega v. Kmart Corp., supra, 26 Cal.4th at pp. 1208-1209, 114 Cal.Rptr.2d 470, 36 P.3d 11). At this early stage, when no facts *326 have yet been developed, the issue is not which of these mental states is required for the tort of negligent transmission of HIV, but what is permissible discovery for a party seeking to prove such a tort. In determining whether the requested discovery satisfies statutory requirements, therefore, we should recognize a duty no broader than is necessary to resolve the current discovery dispute.

In this case, we conclude that the tort of negligent transmission of HIV does not depend solely on actual knowledge of HIV infection and would extend at least to those situations where the actor, under the totality of the circumstances, has reason to know of the infection. Under the reason-to-know standard, "the actor has information from which a person of reasonable intelligence or of the superior intelligence of the actor would infer that the fact in question exists, or that such person would govern his conduct upon the assumption that such fact exists." (Rest.2d Torts, § 12, subd. (1).) In other words, "the actor has knowledge of facts from which a reasonable man of ordinary intelligence or one of the superior intelligence of the actor would either infer the existence of the fact in question or would regard its existence as so highly probable that his conduct would be predicated upon the assumption that the fact did exist." (Id., § 12, com. a., p. 20.)^[1]

Imposing liability for the transmission of HIV where the actor knows or has reason to know he or she is HIV positive is consistent with the general principle of California law that "`[a]ll persons are required to use ordinary care to prevent others being injured as the result of their conduct.'" (Rowland v. Christian, supra, 69 Cal.2d at p. 112, 70 Cal.Rptr. 97, 443 P.2d 561.) "Although it is true that some exceptions have been made to the general principle that a person is liable for injuries caused by his failure to exercise reasonable care in the circumstances, it is clear that in the absence of a statutory provision declaring an exception to the fundamental principle enunciated by section 1714 of the Civil Code, no such exception should be made unless clearly supported by public policy." (Ibid.; see also Randi W. v. Muroc Joint Unified School Dist. (1997) 14 Cal.4th 1066, 1077, 60 Cal.Rptr.2d 263, 929 P.2d 582 (Randi W.).) "Before judicially establishing an exception based on public policy, [we] consider a variety of factors; `the major ones are the foreseeability of harm to the plaintiff, the degree of certainty that the plaintiff suffered injury, the closeness of the connection between the defendant's conduct and the injury suffered, the moral blame attached to the defendant's conduct, the policy of preventing future harm, the extent of the burden to the defendant and consequences to the community of imposing a duty to exercise care with resulting liability for breach, and the availability, cost, and prevalence of insurance for the risk involved.'" (Merrill v. Navegar, Inc. (2001) 26 Cal.4th 465, 477, 110 Cal.Rptr.2d 370, 28 P.3d 116.)

An analysis of these factors does not justify a departure from the general rule in this instance. The factor that "`plays a very significant role in this calculus'" *327 (Randi W., supra, 14 Cal.4th at p. 1077, 60 Cal.Rptr.2d 263, 929 P.2d 582) is the foreseeability of the particular harm, which (like the reason-to-know standard) is assessed by an objective test. (See id. at pp. 1077-1078, 60 Cal.Rptr.2d 263, 929 P.2d 582.) When the actor has reason to know of the HIV infection — i.e., when there is sufficient information to cause a reasonably intelligent actor to infer he or she is infected with the virus or that infection is so highly probable that his or her conduct would be predicated on that assumption — the potential for harm through sexual transmission of the virus is reasonably foreseeable. As to causation, Bridget has plausibly alleged that John infected her during unprotected sex. (See id. at p. 10