It's a commonly held belief: Sperm cells are like runners in an epic race, competing against each other for access to the coveted egg at the finish line. The egg, in turn, waits patiently for the ...

Researchers at Newcastle University in England report they have coaxed the first human sperm cells from embryonic stem cells, in a remarkable demonstration of how quickly the field of stem-cell ...

Katsuhiko Hayashi pulls a clear plastic dish from an incubator and slides it under a microscope. "You really want to see the actual cells, right?" Hayashi asks as he motions toward the microscope.

Oh, brave new world, that has such embryos in it. In a dramatic scientific first, researchers have created synthetic human embryos without using sperm or an egg. No one knows if these embryonic ...

(RNS) — Scientists have created a human embryo without the use of sperm or an egg — a true test-tube baby. Such embryos cannot (yet) develop into full-grown human beings. Even if transplanted into a ...

Well-documented reports spanning 25 years have yielded mounting evidence that sperm counts are tumbling in industrialized countries. (See my April 20, 2017 post Going, Going, Gone? Human Sperm Counts ...

A microscope image of a human egg contains a nucleus taken from a skin cell. (Mitalipov Laboratory at Oregon Health & Science University) WASHINGTON — Oregon scientists used human skin cells to create ...