Central to this all is a zygote, which is what’s formed after a sperm and egg have a little rendezvous. Here’s what happens. A zygote is a fertilized egg.[1]#1 It’s created when sperm meets ...

Identical twins come from a single fertilized egg (called a zygote) that divides in two. They're also called monozygotic or ...

An egg becomes fertilized when a sperm penetrates it, creating a zygote. For the first eight weeks, the developing baby is called an embryo. It looks like a tadpole. At about three weeks ...

This produces a new cell called a zygote, which will mature into an embryo. The number of cells increase by mitosis, and as the embryo develops, the cells begin to differentiate (or specialise).