The more obese you are, the harder it is to get pregnant, and a study just out in the journal Human Reproduction offers some new insight into why. The study, led by Dr. Catherine Racowsky of Brigham and Women's Hospital, found that in severely obese women who underwent fertility treatments, the eggs that failed to fertilize were more likely to have abnormal structures and disorganized chromsomes than the eggs in normal-weight women. In particular, the eggs in the obese women were roughly twice as likely to have double "spindles. See the image below.

Sure, nobody really thinks of worm sperm as being cute and cuddly -- assuming one thinks about them at all -- but who would have thought they were stone cold killers? In a paper published Tuesday in PLOS Biology, a team of researchers who apparently enjoy watching nematodes get jiggy were shocked to learn that male sperm will conduct search-and-destroy missions on females and hermaphrodites of other worm species. Animals of the same genus but different species may mate and produce offspring, but that animal is usually sterile. An example is the mule -- which occurs when you breed a horse and a donkey. Researchers mixed and matched three Caenorhabditis species, cross-breeding male, female and hermaphrodite worms -- worms capable of producing both sperm and eggs in order to reproduce. The males, researchers said, mated indiscriminately when given the opportunity. The hermaphrodites however would attempt to avoid copulation by crawling away from the breeding area when they sensed a male of another species.

A crime wave in Oakland, California's Chinatown has rankled the community heading into the Lunar New Year, prompting celebrities to offer a reward to fight anti-Asian harassment. Meghan, the Duchess of Sussex, said on Thursday a British tabloid had been held to account for its "dehumanizing practices" after she won a privacy claim against the paper for printing extracts of a letter she wrote to her father. Winter weather battered the United States from coast to coast on Thursday as a series of storms expected to last for days mixed with an arctic air mass to bring snow and freezing rain as far south as Texas where there was a deadly multi-vehicle pileup.

It sounds like the setup to a bad joke: Three couples walk into a fertility clinic. But the punch line—what happened to those families at one Los Angeles medical facility in August —is no laughing matter. The embryos from two couples hoping to conceive were mistakenly implanted into a third patient. Today, more than 62, babies born in the US every year—nearly 2 percent—are conceived using technologies like in vitro fertilization IVF.