Researchers have manipulated chromosomes inside a stem cell to produce mice with two biologically male parents. Stem cell biologist Katsuhiko Hayashi of Japan's Osaka University and his team say they ...

A research group is the first in the world to succeed in constructing artificial cell nuclei by injecting purified DNA solution instead of sperm into living mouse eggs. Their findings are published in ...

Katsuhiko Hayashi, a developmental geneticist at Osaka University, is working on ways to make what he calls "artificial" eggs and sperm from any cell in the human body. (Kosuke Okahara for NPR) ...

Most people don’t think much of vultures, despite their vital role as nature’s garbage collectors and first line of defense against diseases. Through the absence of thought, an absence of the birds ...

Artificial ovaries are on the horizon after scientists created the first cellular-level map of human egg formation. The University of Michigan used five donated ovaries to carry out state-of-the-art ...

*When grabbing a quick breakfast at a fast-food restaurant, you might not think too much about what’s in your eggs—but should you? While some chains take pride in using real, freshly cracked eggs, ...

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.