Reproduction

A study of spiders' copulation techniques found that males leave part of their sex organ inside females as a sort of "chastity belt" to deter rivals. "Males can reduce sperm competition and thereby increase their paternity success," Bonn University researchers wrote in the journal Behavioral Ecology. A male only has only seconds to have sex before the larger female kills him. In more than 80% of cases, the tip of the male's genital organ breaks off inside the female.

Female sharks can fertilize their own eggs and give birth without sperm from males, according to a study published Wednesday in the British journal Biology Letters. The joint Northern Ireland-U.S. research analyzed the DNA of a shark born in 2001 at the Henry Doorly Zoo in Omaha. Analysis of the baby shark's DNA found no trace of any chromosomal contribution from a male. Shark experts said this was the first confirmed case in a shark of parthenogenesis, or "virgin birth."

In the final analysis, the federal watchdogs had to make a no-win choice about the bald eagles of Santa Catalina Island. The birds' eggs were still cracking because of the ravages of DDT. The chances of reproducing on their own, at least in the foreseeable future, seemed dubious at best.

CHAD HODGE LIKED #694. She was a 21-year-old college student, 5-feet-5, 135 pounds, with straight brown hair, blue eyes and a narrow nose. She had won 16 awards in high school for academics and music, and scored a 1210 on the SAT. She was outgoing, intelligent, responsible and friendly, or at least she said she was. Chad wanted her to be the mother of his children. But David Craig, Chad's partner of seven years, had his heart set on #685.

WHEN the Massachusetts Supreme Judicial Court voted to legalize gay marriage in 2003, its opinion rested squarely on the argument that determining the best interests of a child "does not turn on a parent's sexual orientation or marital status." Three years later, the top court in neighboring New York also cited the welfare of children -- but took precisely the opposite stance.

It's official: Sex is good for you. Well, at least it's good for yeast. From an evolutionary standpoint, sexual reproduction seems to have many disadvantages over the asexual variety. It wastes time and energy, it mixes up perfectly good genes, and females, who do nearly all of the reproductive work, get to pass on only half their genetic material. So scientists have wondered: Why sex?

Scientists studying the effects of hormone-mimicking chemicals on humans have reported that compounds called phthalates, used in plastics and beauty products and widely found in people, seem to alter the reproductive organs of baby boys. In the first study of humans exposed in the womb to phthalates, the researchers, who examined the genitalia of male babies and toddlers, found a strong relationship between the chemicals and subtle changes in the size and anatomy of the children's genitals.

BATHED IN MOONLIGHT, A FAT SEAL SPRAWLS on the sand and surveys the undulating blanket of silver and green that covers the shore at Long Beach. A strange slapping sound -- wet rubber against rubber -- fills the air. As far as the eye can see, the beach is slippery with grunion, jumpy little fish the size of ballpark franks, flopping around. An excellent late-night buffet.

GRAY whales are having a baby boom, with nearly 180 cow-calf pairs migrating from Baja California, according to a recent census taken from Palos Verdes Peninsula. That's twice as many as in the previous season, which was also productive. Federal wildlife officials made similar observations near Monterey. Not all the whales can be seen, but the counts are considered an indicative sample. Scientists say abundant food in the Bering Sea is helping the whales rebound.

The medical study had profound implications, apparently offering scientific proof of the power of prayer, even the existence of God. The article, with two Columbia University physicians listed as authors, said that women undergoing in vitro fertilization treatments in South Korea were twice as likely to conceive when strangers prayed for them. Making the findings even more spectacular was that the women didn't even know they were being prayed for.