Menopause May Be the Evolutionary Origin of Romantic Relationships -- And Cheating

Menopause is one of the oddest features of human reproductive biology. Not the hot flashes or the forgetfulness, but the fact that older women lose the ability to have babies. Now researchers say that once it appeared, menopause may have had a ripple effect on human mating that helped create the human pair-bond. »9/08/15 6:20pm9/08/15 6:20pm

Meet the Protein That Plugs a Sperm Into an Egg During Fertilization

The successful union of egg and sperm in fertilization depends on a sperm cell’s ability to get through an egg’s thick protective coating and latch itself to its membrane. A study published in the journal Andrology yesterday gives us our first look at the protein responsible for the tie-down. »8/27/15 5:40pm8/27/15 5:40pm

Here’s Why We’re Not Overrun With Adorable Baby Giant Pandas

The Smithsonian’s National Zoo has been part of an international effort to breed highly endangered giant pandas in captivity ever since Richard Nixon visited China in 1972. But in 43 years, they’ve had only two solid successes–cubs Tai Shan and Bao Bao. They hope the new twins born this weekend will make it four. »8/25/15 2:00pm8/25/15 2:00pm

We're Only Beginning To Understand Why Humans Have a Skewed Sex Ratio

The ratio of newborn boys to girls slightly and consistently leans toward males: around 106 boys are born for every 100 girls. If that seems odd to you, it should: the way sperm form suggests that the ratio of X-sperm to Y-sperm should be exactly 50:50–and scientists are only now beginning to understand why the skew… »8/20/15 12:30pm8/20/15 12:30pm

Why the Cervix Is More Amazing Than You Realized

Technically, the cervix is the bottom chunk of the uterus, a circular plug-like mass of tissue dividing the uterine space from the vagina. But where most of the uterine wall is made of smooth muscle, up to 90% of the cervix is built of stiff and unyielding connective tissue. At least, it’s stiff most of the time. »8/14/15 8:30pm8/14/15 8:30pm

The Unusual Mating Habits of This Octopus Totally Blow Biologists' Minds

We all know the sad story of octopus sex, right? They live alone until it’s time to find a mate, they have sex a few times, then the males die. Females live a little longer to lay eggs, but die soon after they hatch. Turns out that the (still officially unnamed) Larger Pacific Striped Octopus breaks all the rules. »8/12/15 5:00pm8/12/15 5:00pm

Here's How a 13-Foot Wide Egg Mass Fits Inside a 5-Foot Squid

On July 9th of this year, divers off the coast of Turkey ran across an enormous lump of gelatinous goo which turned out to be one of the largest squid egg masses ever found. That inspired science writer and squid expert Danna Staaf to make this video explaining how all that goo fit inside a much smaller mother squid. »7/31/15 11:30am7/31/15 11:30am

Australia's Most Infamous Invasive Species Has a Problem with Breeding

Cane toads were first released in Australia in 1935 as part of a government program to control the insects attacking the Queensland cane crop. It didn’t work. Ever since, the toads have been spreading across the country, as fast as they can breed. Which would be even faster, if it weren’t for an odd quirk in their… »7/14/15 7:15pm7/14/15 7:15pm

What Should Parents Do With Their Spare IVF Embryos?

When in vitro fertilization was developed in the 1970s, critics of the technique imagined a world a la Aldous Huxley, filled with assembly-line designer babies. It didn’t turn out like that. Instead, the procedure simply gave infertile couples another route to start a family. But it also created a problem that critics »6/24/15 11:30am6/24/15 11:30am