CONTRARY to popular belief, female mammals do produce new eggs after they are born. That’s true for mice, at least.
While male mammals continually produce sperm from a store of stem cells, biologists have insisted since the 1950s that adult female mammals have no source of new egg cells.
But Jonathan Tilly at the Massachusetts General Hospital in Boston was not convinced. So his team transplanted parts of ovaries from one type of mouse into the ovaries of another type. After a few weeks, the transplants grew new follicles, the sacs in which eggs grow, consisting of cells from the…
