Stem cells have been coaxed into creating everything from liver cells to beating heart tissue. Recently, these versatile cells were even used to make fertile mouse sperm, suggesting that stem cell technology might eventually be able to play a role in the treatment of human infertility. Now two types of stem cells have been turned [...]

Fellas, want a better chance of passing along your genes? Try laying off the fried food. A more healthful diet will not only help you get fitter, but, new research indicates, it might also increase the odds that your sperm are in better shape, too. A whole host of factors might impair male fertility—including alcohol [...]

Sperm face steep odds when set free to fertilize an egg. A slightly faulty tail, a miscalibrated electrical charge on their cell membrane or some other subtle defect can keep these genetic couriers from becoming the lucky, lone swimmer that sires offspring. And now it seems that a surprisingly common genetic mutation might decrease a [...]

As Gwenn Seemel points out in her richly illustrated book, Crime Against Nature, the non-human animal kingdom is chock-full of examples that challenge many of our deeply held beliefs about what is “natural” behavior in everything from sexual preference to lifestyle choices to gender roles and even gender identity. A third gender, male pregnancy and [...]