Your little zygote has now officially turned into an embryo. About eight weeks after fertilization (roughly week 10 of pregnancy), the embryo will turn into what’s known as a fetus. From there ...

Even though the genetic fingerprint of human sperm has been defined, its role in orchestrating fertilization and the development of the early embryo remains vague. Here we show that human male ...

The fusion of sperm and egg gametes during human fertilization establishes a diploid zygote and initiates a series of cell divisions that result in a multicellular embryo. The blastocyst stage is ...

Jef Akst was managing editor of The Scientist, where she started as an intern in 2009 after receiving a master’s degree from Indiana University in April 2009 studying the mating behavior of seahorses.