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 ...

In the animal kingdom, penises can be spiked, split, corkscrewed—even detachable. They're one of the most diverse structures in biology. The human penis is so uniform, it's an anatomical outlier.

The beginning of a new life is an extraordinary event that occurs when the male and female reproductive cells merge. Let’s ...

When sperm meets egg, the start of life is not quiet. Under a special microscope, researchers have watched a tiny light show at fertilization. They see a microscopic flash at fertilization, a burst of ...