Politics should be scientific, just like life begins at conception.
1. The Developing Human, 12th ed. (2024) — Torchia & Persaud
The opening chapter, which carries the same line from recent printings, states:
“Human development is a continuous process that begins when an oocyte (ovum) from a female is fertilized by a sperm (spermatozoon) from a male to form a single-celled zygote. … Cell division, cell migration, programmed cell death (apoptosis), differentiation, growth, and cell rearrangement transform the zygote, a highly specialized, totipotent cell, into a multicellular human being.”
Additionally, it mentions:
“Human development begins at fertilization…”
And:
“The development of a human from a zygote to birth is divided into two main periods, embryonic and fetal.”
The first-week chapter, from the same series, states:
“Human development begins at fertilization when a sperm fuses with an oocyte to form a single cell, the zygote. This highly specialized, totipotent cell … marks the beginning of each of us as a unique individual. The zygote … becomes progressively transformed into a multicellular human being…”
2. Before We Are Born, 9th ed. (2016) — still in the current author line; 11th (2024) not page-checked by me yet:
“Embryology is concerned with the origin and development of a human being from a zygote to birth.”