Many four-legged animals go through embryonic stages that have similar features -- gill arches, a notochord, segmentation, and paddle-like limb buds -- as they develop into different adults.

Discover the fascinating world of extra nipples and supernumerary breasts, a natural variation found in humans and other ...

Closely studied, stem cell lines might give scientists new clues about the growth factors that drive tissue differentiation from the earliest embryonic stage forward. This would permit new ...

Emerging findings suggest that viral DNA may play an important part in how embryos form, right after fertilization.

However, gastrulation, the period beyond this cutoff, represents when the embryo begins to form the eventual body plan, making it an interesting stage to understand early organogenesis. “We’ve just ...

House Bill 1373 would make it so an unborn child would be considered a human being from the moment of fertilization.

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 ...