A woman has conceived when the embryo has been implanted in her uterus […]. The word conception makes explicit reference to pregnancy or gestation, [which] begins with the implantation of the embryo, […] since conception or gestation is an event of the woman, not of the embryo. There is only evidence of the presence of an embryo when it is joined to the woman at a cellular level and the chemical signals of this event can be identified in the woman’s fluids. This signal corresponds to a hormone called chorionic gonadotropin and the earliest that it can be detected is seven days after fertilization, with the embryo already implanted in the endometrium.” 273 (Bold type and underlining added) 182. Furthermore, according to expert witness Monroy Cabra, the term conception is “a medical-scientific term that has been interpreted to mean that it takes place [at the moment of] the fusion of the egg and the spermatozoid.” 274 In similar terms, expert witness Condic considered that “human life begins with the fusion of spermatozoid and egg, an observable ‘moment of conception.’” 275 183. However, in addition to these two possible hypotheses on the moment at which “conception” should be understood to occur, the parties have presented a different thesis regarding the moment when it is believed that the embryo reaches a sufficient degree maturity to be considered a “human being.” Some hold the view that life begins with fertilization, recognizing the zygote as the first corporal manifestation of the continuing process of human development, 276 while others consider that the starting point for the development of the embryo, and subsequently of its human life, is its implantation in the uterus where it has the capacity to add its genetic potential to the mother’s potential. 277 Moreover, others emphasize that life begins when the nervous system develops. 278 184. The Court observes that, while some articles consider that the embryo is a human being, 279 others stress that fertilization occurs in one minute but that the embryo is formed 273 Written summary of the expert opinion provided by Fernando Zegers-Hochschild at the public hearing before the Court (merits report, volume VI, folio 2846). Furthermore, expert witness Zegers-Hochschild stated that “[i]f the intention had been to define the right to protection as of the moment of fertilization, this word would have been used, which is defined perfectly in the dictionary.” Written summary of the expert opinion provided by Fernando Zegers-Hochschild at the public hearing before the Court (merits report, volume VI, folio 2846). 274 Cf. Statement by expert witness Monroy Cabra before the Inter-America Court during the public hearing held in this case. 275 Affidavit prepared by expert witness Condic (merits report, volume V, folio 2592). 276 Cf. In this regard, inter alia: Tanya Lobo Prada, Inicio de la vida (file of annexes to the answering brief, volume I, folios 6653 to 6656), and Maureen L. Condic, Preimplantation Stages of Human Development: The Biological and Moral Status of Early Embryos, en: Is this cell a Human Being?, Springer-Verlag Berlin, 2011 (file of annexes to the answering brief, volume I, folios 6576 a 6594). 277 Cf. Written summary of the expert opinion provided by Fernando Zegers-Hochschild at the public hearing before the Court (merits report, volume VI, folio 2846). 278 In this regard, expert witness Condic indicated that “a number of alternative definitions have been offered as to when human life starts, including syngamy (approximately 24 hours after the fusion of the spermatozoid and egg); implantation (approximately five days after the fusion of the spermatozoid and egg); formation of the primitive streak (approximately 14 days after the fusion of the spermatozoid and egg), and the beginning of the neural function.” Affidavit prepared by expert witness Condic (merits report, volume V, folio 2589). 279 Cf. Inter alia the following scientific articles provided by the State: Tanya Lobo Prada, Inicio de la vida (file of annexes to the answering brief, volume I, folios 6653 to 6656); Maureen L. Condic, Preimplantation Stages of Human Development: The Biological and Moral Status of Early Embryos, in: Is this cell a Human Being?, SpringerVerlag Berlin, 2011 (file of annexes to the answering brief, volume I, folios 6576 to 6594); Maureen L. Condic, When Does Human Life Begin? A Scientific Perspective, in: The Westchester Institute for Ethics and the Human Person, Vol. 1, No.1, 2008 (file of annexes to the answering brief, volume I, folios 6621 to 6648); Jerome Lejeune, El Origen de la Vida Humana, in: Diario ABC, Madrid, 1983 (file of annexes to the answering brief, volume I, folio 6652), and Natalia Lopez Moratalla and María J. Iraburu Elizalde, Los primeros quince días de una vida humana, Ediciones Universidad de Navarra, 2004, (file of annexes to the answering brief, volume VI, folios 9415 to 9503).