The question of when a human life begins is a strictly scientific one and one for which the scientific community has had an empirical, internationally acknowledged answer for a very long time.

For more than a century, the field of human embryology has documented that in human sexual reproduction a new, whole, individual, living human being begins to exist at “first contact” between a sperm and an oocyte/“egg” (the beginning of the process known as fertilization.) Immediately when these two mere cells make first contact and fuse, organism proteins and enzymes specific to humans are produced. One new single-cell human being with his or her own new, unique, and complete set of human DNA begins to exist. This is an internationally recognized empirical fact that has been documented by the Carnegie Stages of Early Human Embryonic Development since 1942, and updated every year since then to the present by the international nomenclature committee (FIPAT). The 23 Carnegie Stages cover human development during the eight-week embryonic period, and a new human being is represented by Carnegie Stage 1a.

The facts surrounding the beginning of a human life are muddled today largely because of the Supreme Court’s reasoning in Roe v. Wade.  Justice Blackmun’s majority opinion states that the beginning of human life could not be determined, because the “disciplines of medicine, philosophy and theology” were “unable to arrive at any consensus.”

What Justice Blackmun failed to acknowledge is that none of the academic disciplines he mentioned have any bearing on the scientific issue of when a human life begins. Human embryology is the only scientific field that specializes in the fine details of human reproduction and empirically documents the stages a human embryo passes through between first contact and the fetal period. The landmark Supreme Court decision was made without the testimony of a single human embryologist.

What doctors, philosophers, and theologians may be qualified to address is the philosophical question of when a human person begins to exist. Personhood refers to a specific set of rights and protections generally accorded to human beings, but society has never reached a universal consensus that all human beings should receive these rights. The rights of personhood have historically been denied to various groups.

Justice Blackmun’s opinion merged the biological with the philosophical. When a human person begins to exist is a philosophical issue.  By contrast, when a human being begins to exist is a scientific issue. Accurate science should be the starting point for resolving the philosophical question, not the reverse. As the philosophy dictum notes, “A small error in the beginning leads to a multitude of errors in the end.”

Because the science has been obscured in philosophy for so long, many people today still believe that the scientific question is not settled.

Contend Projects seeks to reverse this deeply harmful trend. We are working to make the empirical, internationally acknowledged scientific fact of when a human being normally begins simple and accessible for everyone. Accurately informed decisions about human reproduction are relevant to everyone.

Brooke Stanton is the Founder and CEO of Contend Projects.