The majority of fertilized eggs die and are resorbed into the body. ZEISS Microscopy/Flickr, CC BY-SA As an evolutionary biologist whose career has focused on how embryos develop in a wide variety of ...

Many state legislatures are seriously considering human embryos at the earliest stages of development for legal personhood. Total abortion bans that consider humans to have full rights from the moment ...

New Haven, Conn. — In a common metaphor used to describe human fertilization, sperm cells are competitors racing to penetrate a passive egg. But as critics have noted, the description is also a “fairy ...

Long before pregnancy begins, your body is already shaping the conditions for conception. Hormones are signalling, eggs are maturing over months, sperm are regenerating every few weeks, and your ...