121 P.3d 1256 (2005)

Belinda L. JETER, a married woman; William R. Jeter, a married man, Plaintiffs-Appellants,
v.
MAYO CLINIC ARIZONA d/b/a Mayo Clinic Scottsdale and/or Center for Reproductive Medicine, an Arizona corporation, Defendant-Appellee.

No. 1 CA-CV 04-0048.

Court of Appeals of Arizona, Division 1, Department E.

October 27, 2005.

*1258 Levenbaum & Cohen by Geoffrey M. Trachtenberg, Phoenix, Attorneys for Plaintiffs-Appellants.

Snell & Wilmer L.L.P. by Daniel J. McAuliffe, Barry D. Halpern, GinaMarie Slattery, Stephanie V. Hackett, Phoenix, Attorneys for Defendant-Appellee.

OPINION

KESSLER, Judge.

¶ 1 Belinda and William Jeter ("the Jeters") appeal from the dismissal of their lawsuit against the Mayo Clinic Arizona doing business as Mayo Clinic Scottsdale and/or the Center for Reproductive Medicine ("Mayo"). The Jeters sued Mayo for the alleged negligent destruction or loss of five of the Jeters' frozen human pre-implantation embryos or pre-embryos,^[1] which Mayo agreed to cryopreserve and store.

¶ 2 The superior court held the Jeters had failed to state a claim upon which relief could be granted and dismissed their wrongful death claim because the pre-embryos were not "persons" under Arizona's wrongful death statutes, Arizona Revised Statutes ("A.R.S.") sections 12-611 to -613 (2003). It also held Arizona did not recognize the Jeters' *1259 claim for negligent loss of irreplaceable property. The court further rejected the Jeters' breach of fiduciary duty and breach of bailment contract claims as barred by Arizona's Medical Malpractice Act, A.R.S. §§ 12-561 to -594 (2003 & Supp.2004).

¶ 3 For the reasons discussed below, we affirm the superior court's dismissal of the wrongful death claim and hold that absent legislative action expanding the wrongful death statutes, as a matter of law, a cryopreserved, three-day old fertilized human egg is not a "person" for purposes of that statute. However, we reverse the dismissal of the other three claims and remand for further proceedings consistent with this opinion.

FACTUAL AND PROCEDURAL BACKGROUND

¶ 4 Since the complaint was dismissed at the pleading stage for failure to state a claim, we review the well-pleaded facts alleged in the complaint as true. Shannon v. Butler Homes, 102 Ariz. 312, 315, 428 P.2d 990, 993 (1967) (court will accept as true only well-pleaded facts). However, we do not accept as true allegations consisting of conclusions of law, inferences or deductions that are not necessarily implied by well-pleaded facts, unreasonable inferences or unsupported conclusions from such facts, or legal conclusions alleged as facts. Id.; Dockery v. Central Ariz. Light and Power Co., 45 Ariz. 434, 439, 45 P.2d 656, 658 (1935) (only well-pleaded facts accepted as true, not inferences that are not necessarily implied by such facts); Kellogg v. Nebraska Dep't of Corr., 269 Neb. 40, 690 N.W.2d 574, 578 (2005) (court will ignore legal conclusions in form of factual allegations).

¶ 5 The Jeters went to Mayo for information on medical procedures that would assist them in conceiving a child. Mayo offered certain services for harvesting, storing and implanting pre-embryos, including in vitro fertilization. With the consent of the Jeters, Dr. Anita Singh at Mayo retrieved or harvested multiple eggs from Belinda Jeter, which were fertilized in vitro (outside Mrs. Jeter's womb) with William Jeter's sperm. The resulting zygotes were permitted to progress through several divisions in the laboratory over a period of forty-eight to seventy-two hours, developing from single-cell organisms to two- to eight-cell organisms. While the Jeters' complaint refers to these fertilized eggs as "viable embryos," such a characterization is a conclusion that is not necessarily implied from the well-pleaded facts. Pursuant to a written consent form, Mayo and the Jeters agreed to have Mayo cryopreserve and store the pre-embryos.^[2]

¶ 6 Belinda Jeter underwent two unsuccessful non-surgical in vitro fertilization procedures at Mayo attempting to implant the pre-embryos into her womb. The Jeters then began looking at alternative procedures.

¶ 7 The Jeters decided to utilize the services of Dr. Jay Nemiro at the Arizona Center for Fertility Studies Ltd. ("Arizona Center"). Dr. Nemiro offered them an alternative procedure called a tubal embryo transfer. A tubal embryo transfer also requires initial egg retrieval and fertilization of the eggs in a laboratory. Unlike the procedures at Mayo, however, in a tubal embryo transfer the physician injects the pre-embryos into a woman's fallopian tube(s) during a laparoscopy, enabling them to reach the uterus via their biological route.

¶ 8 The Jeters made arrangements to personally transfer their ten remaining cryopreserved pre-embyros from Mayo to the Arizona Center, obtaining proper storage equipment and arranging for delivery to the Arizona Center. The Jeters executed a transfer request form, obtaining Mayo's release of the remaining cryopreserved pre-embryos in four labeled straws.

*1260 ¶ 9 The Jeters alleged they transferred the pre-embryos to the Arizona Center. Belinda Jeter then went to the Arizona Center for a tubal embryo transfer. Before the surgical implantation, the doctor told her that two of the four straws did not contain, and had never contained, any embryonic matter. If this is accurate, Mayo had actually produced only five of the Jeters' ten remaining pre-embyros. Mayo failed to account for the allegedly missing pre-embryos.

¶ 10 The Jeters proceeded with the tubal embryo transfer at the Arizona Center with the five remaining pre-embryos. The procedure was successful and Belinda Jeter conceived and delivered a daughter. However, the Jeters would like to have more children and now must undergo the additional discomfort and cost of harvesting and fertilizing more eggs. In addition, the Jeters remain concerned about the fate of the allegedly missing pre-embryos, wondering whether Mayo lost or destroyed them or whether Mayo may have given them to the wrong people, resulting in the birth of one or more of the Jeters' biological children to another woman.

¶ 11 The Jeters sued Mayo alleging four claims. Count One asserted a claim for "Negligence—Loss of Potential Children" under Arizona's wrongful death statutes. Count Two asserted a claim for "Negligence—Loss of Irreplaceable Property." Under that count, the Jeters alleged Mayo had breached its duty to store and safeguard the fertilized eggs. Count Three asserted a claim for "Breach of Fiduciary Duty," alleging that, because the organisms were "potentially viable human beings, their custody was entitled to `special respect' and [the] highest standards of care." Finally, Count Four asserted a claim for breach of a bailment contract.

¶ 12 Mayo moved to dismiss the complaint for failure to state a claim, arguing as to Count One that the cryopreserved three-day old, eight-cell pre-embryos were not "persons" under the Arizona wrongful death statutes. Mayo further asserted as to Count Two that Arizona did not recognize a claim for loss of irreplaceable property. As to Count Three, Mayo argued that the medical malpractice act barred the claim for breach of fiduciary duty because it was not an enumerated cause of action against a health care provider allowed by that act. Finally, as to Count Four, Mayo asserted that A.R.S. § 12-562(C) (Supp.2003) barred the breach of bailment contract claim because there was no written bailment contract between the parties as required by that statute.

¶ 13 The Jeters opposed the motion, asking the court to recognize the first two causes of action and to hold the medical malpractice act unconstitutional if it abrogated their claims. They also contended they had a written bailment contract with Mayo.

¶ 14 The superior court granted Mayo's motion, holding:

The Court specifically finds that the wrongful death statute does not provide relief for frozen cell embryos and that the same are not "persons."

The Court also specifically finds that there is no common law cause of action in Arizona for the alleged negligent loss of viable human embryos.

And lastly, the Court finds that the Arizona medical negligence (malpractice) act is not unconstitutional.

¶ 15 The Jeters moved for partial reconsideration and clarification of the ruling. They asked the court to reconsider its holding that Arizona did not recognize a common law cause of action for negligent loss of irreplaceable property. They further asked the court to clarify its ruling as to their claim for breach of bailment contract, asserting they had shown they had a written contract with Mayo.

¶ 16 The superior court denied the motion for reconsideration. The court noted that perhaps the third paragraph of its prior minute entry (regarding the constitutionality of the medical malpractice act) could be removed but stated that this "entire `subject' needs to be handled by the Appellate Courts and/or Legislature." The court entered judgment granting Mayo's motion to dismiss, and the Jeters timely filed this appeal.^[3]

*1261 ISSUES

¶ 17 The Jeters argue the superior court improperly dismissed their complaint because: (1) the Jeters' cryopreserved pre-embryos were "persons" under the Arizona wrongful death statutes; (2) Arizona recognizes a cause of action for the negligent loss or destruction of the cryopreserved pre-embryos; (3) to the extent A.R.S. §§ 12-561(1) and -562(A) bar the Jeters' claims for breach of fiduciary duty and breach of bailment contract, those statutes are unconstitutional; and (4) the Jeters adequately pled the existence of a written bailment contract as required by A.R.S. § 12-562(C).

DISCUSSION

I. Jurisdiction and Standard of Review

¶ 18 We have jurisdiction over this appeal pursuant to A.R.S. § 12-2101(B) (2003). We review de novo an order dismissing a complaint for failure to state a claim. Fairway Constr., Inc. v. Ahern, 193 Ariz. 122, 124, ¶ 4, 970 P.2d 954, 956 (App.1998). We will affirm such a dismissal only if "satisfied as a matter of law that plaintiffs would not be entitled to relief under any interpretation of the facts susceptible of proof." Fidelity Sec. Life Co. v. State of Arizona Dep't of Ins., 191 Ariz. 222, 224, ¶ 4, 954 P.2d 580, 582 (1998). We review de novo the interpretation of a statute. Open Primary Elections Now v. Bayless, 193 Ariz. 43, 46, ¶ 9, 969 P.2d 649, 652 (1998).

II. Summary of Holding

¶ 19 For the reasons stated below, we hold that, given the current unsettled discussion over when life begins in this context, it is best left to the Arizona Legislature, not the courts, to decide whether to include a three-day-old, eight-cell cryopreserved pre-embryo within the statutory definition of "person" under the wrongful death statutes. Accordingly, we affirm the superior court's dismissal of the wrongful death claim. However, we also hold that the Jeters stated causes of action for negligent loss or destruction of the pre-embryos, breach of fiduciary duty and breach of a bailment contract, and therefore we reverse the superior court's dismissal of those claims.

III. The Claim Under Arizona's Wrongful Death Statutes

¶ 20 The superior court correctly held that under current Arizona law a cryopreserved, three-day-old eight-cell pre-embryo is not a "person" for whose loss or destruction the Jeters can recover under Arizona's wrongful death statutes as interpreted in Summerfield v. Superior Court, 144 Ariz. 467, 698 P.2d 712 (1985). We decline the Jeters' request to broadly interpret the term "person" under the wrongful death statutes to conception outside a woman's womb. We do so based on Summerfield, general principles of statutory construction, the status of scientific knowledge concerning embryonic development, the ongoing discussion concerning when life begins, the unintended consequences that may result from such a judicial holding and case law from other jurisdictions. Given these factors and principles, we conclude that, subject to constitutional limitations, a decision to expand the definition of "person" for purposes of the wrongful death statutes beyond that stated in Summerfield is best left to the Legislature.

A. Summerfield and Arizona's Wrongful Death Statutes

¶ 21 Arizona's wrongful death statute provides, in pertinent part:

When death of a person is caused by wrongful act, neglect or default, and the act, neglect or default is such as would, if death had not ensued, have entitled the party injured to maintain an action to recover damages in respect thereof, then, and in every such case, the person who or the corporation which would have been liable if death had not ensued shall be liable to an action for damages, notwithstanding the death of the person injured....

*1262 A.R.S. § 12-611 (emphasis added). The Arizona Legislature has not defined the meaning of "person" under the statute. In Summerfield, our supreme court interpreted that word's meaning. Disapproving a prior decision that required a live birth for a fetus to be considered a person under the wrongful death statutes, the court adopted a more expansive view of the term "person" under the wrongful death statutes, holding it to include a viable fetus, meaning the ability of a fetus to live outside the womb. 144 Ariz. at 477-79, 698 P.2d at 722-24 (disapproving Kilmer v. Hicks, 22 Ariz.App. 552, 529 P.2d 706 (1974)).

¶ 22 In Summerfield, the plaintiffs brought a wrongful death action, alleging that their thirty-seven-week-old fetus was stillborn as a result of the defendant physician's medical malpractice. Id. at 470, 698 P.2d at 715. The trial court dismissed the action on the basis that a fetus was not a "person" under A.R.S. § 12-611. Id. The supreme court reversed, holding that the term "person" as used in the wrongful death statutes "encompasses a stillborn, viable fetus" for which a wrongful death claim could be brought. Id. at 479, 698 P.2d at 724 (emphasis added).

¶ 23 Of particular import to this case is the supreme court's restriction of its holding to only allow wrongful death claims arising from the death of a viable fetus. Id. at 477, 698 P.2d at 722. The court recognized that viability was still somewhat of an arbitrary line, but determined that it was a "less arbitrary and more logical point than the moment of birth." Id. The court stated that one of the prerequisites for recovery under the wrongful death statutes "is the ability of the injured party to maintain an action if death had not ensued." Id. at 475, 698 P.2d at 720. The court held that "the common law now recognizes that it is the ability of the fetus to sustain life independently of the mother's body that should determine when tort law should recognize it as a `person' whose loss is compensable to the survivors." Id. at 477, 698 P.2d at 722. The court agreed with the Missouri Supreme Court that if "[b]ut for the injury" a viable fetus would have been born, thereby entitling the child to sue for his or her injury, the fetus is a "person" for purposes of a wrongful death action. Id. at 475, 698 P.2d at 720 (citing O'Grady v. Brown, 654 S.W.2d 904, 911 (Mo.1983)).

¶ 24 Unlike a viable fetus, many variables affect whether a fertilized egg outside the womb will eventually result in the birth of a child, see ¶ 46, infra. This makes it speculative at best to conclude that "but for the injury" to the fertilized egg a child would have been born and therefore entitled to bring suit for the injury. See, generally, Robertson v. Sixpence Inns of America, Inc., 163 Ariz. 539, 546, 789 P.2d 1040, 1047 (1990)(holding causation cannot be left to speculation). The absence of this prerequisite to "personhood" supports a conclusion that pre-implantation fertilized human eggs are not "persons" for purposes of § 12-611.

¶ 25 Other considerations which led to the result in Summerfield also support our conclusion not to further judicially broaden the meaning of "person" under the wrongful death statute without express Legislative direction. The Summerfield court examined the Legislature's goals in enacting the wrongful death statute and concluded that including a viable fetus in the definition of "person" furthered these goals. Id. at 476, 789 P.2d at 721. First, the court identified compensation to survivors for the loss of victims as a goal in enacting the wrongful death statute. Id. Second, the court recognized protection of a viable fetus as a legislative goal in laws concerning abortions and crimes. Id. In light of this overall legislative policy of compensation and protection of viable fetuses, the court construed the wrongful death statute as giving parents a remedy when their viable fetus is negligently killed. Id.

¶ 26 While allowing a parent to maintain a wrongful death action for loss of a pre-implantation fertilized egg may further the compensation goal, it would not further any protection goal advanced by the Legislature. Currently, no statute in Arizona protects fertilized eggs outside the womb in the way statutes protect fetuses and embryos implanted in wombs. See, e.g., A.R.S. § 13-1103(A)(5),(B)(providing a person commits manslaughter for knowingly or recklessly causing death of unborn child in womb at any *1263 stage of development by physically harming mother). Compare A.R.S. § 36-2301 (imposing duty on physicians performing abortions to maintain life of any fetus or embryo delivered alive). Consequently, and because parents may otherwise obtain compensation by filing other actions for loss of pre-implantation fertilized eggs, legislative policy would not be furthered by including such fertilized eggs within the definition of "person" for purposes of the wrongful death statute.

¶ 27 The Summerfield court also surveyed other jurisdictions and concluded that the common law "recognizes that it is the ability of the fetus to sustain life independently of the mother's body that should determine when tort law should recognize it as a `person' whose loss is compensable to the survivors." Summerfield, 144 Ariz. at 477, 698 P.2d at 722. In the twenty years since Summerfield, most jurisdictions have limited the definition of "person" in wrongful death statutes to a point after the fetus is viable. See, ¶¶ 55-59, infra, and cases cited therein. Thus, the common law does not currently require "the growth and evolution" of Arizona's wrongful death statutes to include a pre-implantation fertilized egg within the definition of "person" in A.R.S. § 12-611. See Summerfield, 144 Ariz. at 473, 698 P.2d at 718.

¶ 28 In conclusion, the Summerfield model of analysis yields a conclusion that a fertilized human egg outside the womb is not a "person" within the meaning of A.R.S. § 12-611 regardless of whether that fertilized egg constitutes human life or potential human life.

B. Principles of Statutory Construction

¶ 29 Principles of statutory construction also support our conclusion that the wrongful death statute does not encompass the loss of a cryopreserved pre-embryo. The ultimate goal of statutory construction is to give effect to the Legislature's intent. People's Choice TV Corp. v. City of Tucson, 202 Ariz. 401, 403, ¶ 7, 46 P.3d 412, 414 (2002). When seeking the intent of the Legislature, we first look to the plain wording of the statute. In re Adam P., 201 Ariz. 289, 291, ¶ 12, 34 P.3d 398, 400 (App.2001). If that language is unambiguous, we apply it without use of other means of statutory construction. Aros v. Beneficial Ariz., Inc., 194 Ariz. 62, 66, 977 P.2d 784, 788 (1999). However, when the statutory language does not make that intent clear, we construe the statute to ascertain that intent using a number of principles of statutory construction. Id. Each such principle relevant to the issue presented here supports our conclusion that this Court should not interpret the term "person" as used in A.R.S. § 12-611 as including a cryopreserved three-day-old pre-embryo.

¶ 30 As noted above, A.R.S. § 12-611 simply refers to a "person" without further explanation. As such, the statutory language is not clear whether the Legislature intended to protect such pre-embryos as persons for purposes of those statutes. Accordingly, we must apply various principles to determine the Legislature's intent.

¶ 31 First, if the Legislature's intent is not clear on the face of the statute, we look to see whether the Legislature has amended or recodified the statute following a judicial construction of the statute. If the Legislature has so acted, it is presumed the Legislature knew of the judicial construction and by amending or recodifying the statute without addressing that construction, approved of the judicial decision. Fisher v. Kaufman, 201 Ariz. 500, 502, ¶ 12, 38 P.3d 38, 40 (App.2001) (Legislature is presumed to know of court decisions interpreting statutory language and to approve those decisions when it retains the language.); Hause v. City of Tucson, 199 Ariz. 499, 502, ¶ 10, 19 P.3d 640, 643 (App. 2001) (Court will not presume Legislature intended to supersede supreme court's interpretation of statute unless it did so explicitly or such a conclusion is clearly required by the language or effect of the statute; when Legislature reenacts statute without change, court presumes the Legislature adopted supreme court's interpretation.) (citing Madrigal v. Indus. Comm'n, 69 Ariz. 138, 144, 210 P.2d 967, 971 (1949)).

¶ 32 The supreme court decided Summerfield in 1985. In 2000, the Legislature amended A.R.S. § 12-612 to address who can be a party plaintiff for a child. 2000 Ariz. *1264 Sess. Laws, ch. 182, § 1. Pursuant to the above rules of statutory construction, the Legislature knew of Summerfield and did not amend any language in the wrongful death statute to address whether the Act applied to the death of a nonviable fetus, no less a cryopreserved three-day-old pre-embryo. Accordingly, we presume the Legislature approved of the supreme court's construction of the term "person" to include a "viable" fetus.^[4]

¶ 33 Second, we must not construe a statute to reach an absurd result. Bilke v. State, 206 Ariz. 462, 464, ¶ 11, 80 P.3d 269, 271 (2003). A court must also consider the consequences of those constructions to see what light they shed on the proper interpretation. Walter v. Wilkinson, 198 Ariz. 431, 433, ¶ 10, 10 P.3d 1218, 1220 (App.2000). If this Court were to interpret the concept of "person" for purposes of the wrongful death statutes to include cryopreserved three-day-old eight-cell pre-embryos such as those involved here, a number of difficulties could arise. For example, it is unclear how long a pre-embryo can safely remain in a cryopreserved state.^[5] If the female donor decided she did not want another child, the clinic would be faced with the dilemma of allowing the pre-embryos to be irretrievably damaged by indefinite storage and face potential liability for a wrongful death.

¶ 34 Each of these principles of statutory construction weighs in favor of preserving the current test under Summerfield for a "person" for purposes of our wrongful death statutes—that of a viable fetus. Moreover, the special types of respect due embryos and pre-embryos can be met without the need to broadly expand the definition of "person" for the wrongful death statutes.

C. The Jeters' Claim to Expand the Definition of Viability

¶ 35 Given the decision-making model utilized in Summerfield and principles of statutory interpretation, we could conclude that the Jeters' claim for wrongful death of the pre-embryos fails as a matter of law. However, as the court made clear in Summerfield, 144 Ariz. at 473, 698 P.2d at 718, in the context of the wrongful death statute the courts should play an important role in the development of the common-law attributes of wrongful death actions, especially when the Legislature has not "occupied the field so fully as to preclude judicial development." 144 Ariz. at 472-73, 698 P.2d at 717-18. The Jeters invite this Court to participate in that evolution, pointing out that the court in Summerfield relied in part on advances of scientific knowledge concerning embryonic development to expand the meaning of the term *1265 "person" in the wrongful death statute. Id. at 473-77, 698 P.2d at 716-20. The Jeters contend that since 1984, when Summerfield was decided, knowledge of embryonic development and viability has advanced to the point where, as a matter of law, courts can and should broaden the meaning of "person" to include cryopreserved pre-embryos.

¶ 36 It is important to understand what the Jeters argue. Neither in the superior court nor in this Court did the Jeters claim that they had evidence to support a view that a cryopreserved pre-embryo fits within the definition of a viable fetus as discussed in Summerfield, that is, an entity which can presently survive to birth outside of the womb. Rather, relying on various treatises,^[6] the Jeters contend that medical science has so advanced since the supreme court decided Summerfield, that as a matter of law and statutory construction, this Court should expand the definition of a "person" articulated in Summerfield to allow wrongful death actions for the loss of cryopreserved three-day-old eight-celled pre-embryos because they have the potential to become viable. They contend those medical advances allow such pre-embryos to maintain "extrauterine" life via the cryopreservation process.

¶ 37 Particularly given the current scientific, ethical, social and legal controversy over when life should be considered to begin, we decline to so interpret the meaning of the term "person" in the wrongful death statute. Absent a specific legislative definition of "person," we could decide whether a broader common-law interpretation of that term is legally appropriate. Summerfield, 144 Ariz. at 472-73, 698 P.2d at 717-18. However, as a matter of judicial restraint such a decision currently is best left to the Legislature subject to any constitutional constraints.

¶ 38 We decline the Jeters' invitation for two reasons. First, their position broadens the definition of viability to a point of "potential viability," whereas the court in Summerfield was using viability to mean the present ability of the entity to exist and fully develop to birth outside of the womb. Our understanding of scientific knowledge at the current time does not support a broadening of this legal definition to potential viability absent legislative direction. Second, such a broadening of the term "person" requires balancing of a number of other factors and societal interests best left to the Legislature.

1. Potential vs. Present Viability

¶ 39 The Jeters claim that given scientific advancements, courts should, as a matter of law, broaden the term "person" in this context to include pre-embryos. The Jeters do not contend that three-day-old, eight-celled cryopreserved pre-embryos can exist and develop into viable entities ex utero. Rather, they claim that it is the pre-embryos potential to become viable, if later implanted in a womb, which should govern our decision.

¶ 40 As a legal matter, this argument misstates the idea of viability. In this context, "viability" means that, once implanted in the womb, the embryo has reached a stage of development that, if it is taken out of the womb, it would be viable. Thibert v. Milka, 419 Mass. 693, 646 N.E.2d 1025, 1026-27 (1995).^[7]

¶ 41 Current scientific knowledge concerning embryonic development underscores the difference between a viable fetus in vivo and an eight-cell, three-day-old pre-embryo in vitro. Such knowledge is important to help guide, but not dictate resolutions of the problem. Maienschein at 10.^[8]

*1266 ¶ 42 We summarize our understanding of the current state of knowledge of embryonic development not to dictate or prejudge any decision as to when life should be considered to begin for purposes of a wrongful death action. Rather, we do so to fairly respond to the Jeters' claim that, as a matter of law, a court should re-interpret the wrongful death statutes to define "person" to include a cryopreserved three-day old, eight-celled fertilized egg. The following summary is taken from a number of sources, including Maienschein at 256-62; Ronald M. Green, The Human Embryo Research Debates—Bioethics in the Vortex of Controversy at 6-8, 27-29, 42 (2001) ("Green"); Andrea L. Bonnicksen, Crafting a Cloning Policy—From Dolly to Stem Cells at 20-25 & 69-71 (2002) ("Bonnicksen"); James A. Thomson, Human Embryonic Stem Cells, in The Human Embryonic Stem Cell Debate (Suzanne Holland, Karen LeBacqz, Laurie Zoloth, eds.) (2001) ("Holland") at 15; Thomas A. Shannon, From the Micro to the Macro, in Holland at 178; Kiessling at 1055-65.

¶ 43 Traditionally an egg is fertilized by the combining of an egg and a sperm, which are collectively referred to as gametes. Once an egg is fertilized, whether in vivo or in vitro, it can be referred to as a one-cell zygote. After two to three days of division, the cells are blastomeres. At that time, the pre-embryo consists of eight cells, all of which are totipotent, meaning that any of the cells could develop into any type of tissue and could theoretically develop into eight separate fetuses. At four to six days, it is .1 millimeter in diameter, at which time the cells begin to separate and migrate.

¶ 44 If growth proceeds normally, the outer cells will eventually become the placenta and tissue supporting the fetus while the inner cells, called the inner cell mass, will become the fetus. At five to six days of development, it is called a blastocyst and consists of a hollow ball of approximately 100 cells. These cells are pluripotent, meaning that they have started to specialize but can still develop into various types of tissue. Scientists are still learning how the cells function at this point of development.

¶ 45 By the ninth or tenth day, if in vivo and if it has continued to develop, the blastocyst will implant in the uterine wall.^[9] At day fourteen, a critical development occurs—the creation of the primitive streak with three layers of specialized cells that will develop into all the fetus' tissues and cells if development continues. At this point it has approximately 2000 cells; the groove or middle line reflects a head-tail and left-right orientation. By day 22 of normal development, the heart begins to beat, and, by day 40, some body parts are recognizable in primitive form. At eight weeks, if it has continued to develop, most of the organ systems have appeared.

¶ 46 As noted above, the occurrence of each of these events depends on the ability of the organism to continue to develop. This is problematic because the percentage of pre-embryos that develop into a fetus and a live birth is not high, regardless whether it is developing in vivo or in vitro, but it is significantly lower for cryopreserved pre-embryos. The President's Council