Here are a few sources.
[1] See, e.g., Condic, When Does Human Life Begin? A Scientific Perspective (The Westchester Institute for Ethics & the Human Person Oct. 2008),
http://bdfund.org/wordpress/wpcontent/uploads/2012/06/wi_whitepaper_life_print.pdf; George & Tollefsen, EMBRYO 39 (2008).
Not a peer reviewed paper or a link to consensus by embryologists.
[2] Marsden et al., Model systems for membrane fusion, CHEM. SOC. REV. 40 (3): 1572 (Mar. 2011) (emphasis added).
Membrane fusion has an overarching influence on living organisms. The fusion of sperm and egg membranes initiates the life of a sexually reproducing organism. Intracellular membrane fusion facilitates molecular trafficking within every cell of the organism during its entire lifetime, and virus-cell membrane fusion may signal the end of the organism's life. Considering its importance, surprisingly little is known about the molecular-level mechanism of membrane fusion. Due to the complexity of a living cell, observations often leave room for ambiguity in interpretation. Therefore artificial model systems composed of only a few components are being used to further our understanding of controlled fusion processes. In this critical review we first give an overview of the hypothesized mechanism of membrane fusion and the techniques that are used to investigate it, and then present a selection of non-targeted and targeted model systems, finishing with current applications and predictions on future developments
Not about When a human being is formed
[3] Okada et al., A role for the elongator complex in zygotic paternal genome demethylation, NATURE 463:554 (Jan. 28, 2010) (emphasis added).
The life cycle of mammals begins when a sperm enters an egg. Immediately after fertilization, both the maternal and paternal genomes undergo dramatic reprogramming to prepare for the transition from germ cell to somatic cell transcription programs. One of the molecular events that takes place during this transition is the demethylation of the paternal genome. Despite extensive efforts, the factors responsible for paternal DNA demethylation have not been identified. To search for such factors, we developed a live cell imaging system that allows us to monitor the paternal DNA methylation state in zygotes. Through short-interfering-RNA-mediated knockdown in mouse zygotes, we identified Elp3 (also called KAT9), a component of the elongator complex, to be important for paternal DNA demethylation. We demonstrate that knockdown of Elp3 impairs paternal DNA demethylation as indicated by reporter binding, immunostaining and bisulphite sequencing. Similar results were also obtained when other elongator components, Elp1 and Elp4, were knocked down. Importantly, injection of messenger RNA encoding the Elp3 radical SAM domain mutant, but not the HAT domain mutant, into MII oocytes before fertilization also impaired paternal DNA demethylation, indicating that the SAM radical domain is involved in the demethylation process. Our study not only establishes a critical role for the elongator complex in zygotic paternal genome demethylation, but also indicates that the demethylation process may be mediated through a reaction that requires an intact radical SAM domain.
Not about When a human being is formed
[4] Signorelli et al., Kinases, phosphatases and proteases during sperm capacitation, CELL TISSUE RES. 349(3):765 (Mar. 20, 2012) (emphasis added).
Fertilization is the process by which male and female haploid gametes (sperm and egg) unite to produce a genetically distinct individual. In mammals, fertilization involves a number of sequential steps, including sperm migration through the female genital tract, sperm penetration through the cumulus mass, sperm adhesion and binding to the zona pellucida, acrosome exocytosis, sperm penetration through the zona and fusion of the sperm and egg plasma membranes. However, freshly [bless and do not curse][bless and do not curse][bless and do not curse][bless and do not curse][bless and do not curse][bless and do not curse][bless and do not curse][bless and do not curse][bless and do not curse][bless and do not curse] sperm are not capable of fertilizing an oocyte. They must first undergo a series of biochemical and physiological changes, collectively known as capacitation, before acquiring fertilizing capabilities. Several molecules are required for successful capacitation and in vitro fertilization; these include bicarbonate, serum albumin (normally bovine serum albumin, BSA) and Ca(2+). Bicarbonate activates the sperm protein soluble adenylyl cyclase (SACY), which results in increased levels of cAMP and cAMP-dependent protein kinase (PKA) activation. The response to bicarbonate is fast and cAMP levels increase within 60 s followed by an increase in PKA activity. Several studies with an anti-phospho-PKA substrate antibody have demonstrated a rapid increase in protein phosphorylation in human, mouse and boar sperm. The target proteins of PKA are not known and the precise role of BSA during capacitation is unclear. Most of the studies provide support for the idea that BSA acts by removing cholesterol from the sperm. The loss of cholesterol has been suggested to affect the bilayer of the sperm plasma membrane making it more fusogenic. The relationship between cholesterol loss and the activation of the cAMP/PKA pathway is also unclear. During early stages of capacitation, Ca(2+) might be involved in the stimulation of SACY, although definitive proof is lacking. Protein tyrosine phosphorylation is another landmark of capacitation but occurs during the late stages of capacitation on a different time-scale from cAMP/PKA activation. Additionally, the tyrosine kinases present in sperm are not well characterized. Although protein phosphorylation depends upon the balanced action of protein kinases and protein phosphatase, we have even less information regarding the role of protein phosphatases during sperm capacitation. Over the last few years, several reports have pointed out that the ubiquitin-proteasome system might play a role during sperm capacitation, acrosome reaction and/or sperm-egg fusion. In the present review, we summarize the information regarding the role of protein kinases, phosphatases and the proteasome during sperm capacitation. Where appropriate, we give examples of the way that these molecules interact and regulate each other's activities.
Not about When a human being is formed
[5] Coy et al., Roles of the oviduct in mammalian fertilization, REPRODUCTION 144 (6): 649 (Oct. 1, 2012) (emphasis added).
The oviduct or Fallopian tube is the anatomical region where every new life begins in mammalian species. After a long journey, the spermatozoa meet the oocyte in the specific site of the oviduct named ampulla and fertilization takes place. The successful fertilization depends on several biological processes that occur in the oviduct some hours before this rendezvous and affect both gametes. Estrogen and progesterone, released from the ovary, orchestrate a series of changes by genomic and nongenomic pathways in the oviductal epithelium affecting gene expression, proteome, and secretion of its cells into the fluid bathing the oviductal lumen. In addition, new regulatory molecules are being discovered playing important roles in oviductal physiology and fertilization. The present review tries to describe these processes, building a comprehensive map of the physiology of the oviduct, to better understand the importance of this organ in reproduction. With this purpose, gamete transport, sperm and oocyte changes in the oviductal environment, and other interactions between gametes and oviduct are discussed in light of recent publications in the field.
Not about When a human being is formed
[6] Marcello et al., Fertilization, ADV. EXP. BIOL. 757:321 (2013) (emphasis added).
This is a textbook, not a peer reviewed paper or a link to consensus by embryologists.
[7] National Institutes of Health, Medline Plus Merriam-Webster Medical Dictionary (2013),
http://www.merriamwebster.com/medlineplus/fertilization (emphasis added).
404 - Not Found
[8] Moore & Persaud, THE DEVELOPING HUMAN 16 (7th ed. 2003) (emphasis added).
This is a textbook, not a peer reviewed paper or a link to consensus by embryologists.
[9] For an overview of how the definition of “pregnancy” has changed, see Gacek, Conceiving Pregnancy: U.S. Medical Dictionaries and Their Definitions of Conception and Pregnancy, FRC INSIGHT PAPER (Apr. 2009),
http://downloads.frc.org/EF/ EF09D12.pdf
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You do understand that simply searching for words like "Human being" in a science article does not make anything that match it "a scientific fact" correct? That science has to be something that directly addresses the question at hand. This is why no court has been convinced by this "science". It is not because they are biased but because this is a question science does not address no matter how many pro life sites attempt to desperately piece a case together with text books and dictionaries.
