What came first, the chicken or the egg? If we’re talking about eggs in general, then the latter, but a new study of an ...

When a sperm cell fertilizes an egg, the resulting zygote has the genetic information from both cells but only cytoplasm—the substance that fills the cell—from the egg. That means that any of ...

All our adult cells come from a single cell, called the fertilized egg (or zygote), which during our development will divide and differentiate into specialized cells and adult stem cells.