The extremely rare event, thought to be caused by two sperm cells fertilizing the same egg simultaneously, was last reported in 2007.

Videos reveal how a female squid fertilizes her eggs—one at a time and without spilling much stored sperm.

A 37-year-old simiang gibbon on birth control unexpectedly gave birth at the San Diego Zoo.

Nest predation of shorebirds that raise young in the Arctic are up threefold since the mid-20th century, and climate change may be to blame, according to a study.

A University of Georgia fisheries researcher, who is head of the school’s program to farm-raise sturgeon and sell their salt-cured eggs, is expected to retire this week.

Researchers believe the genetic locus affects the regulation of another gene involved in sexual function.

For flycatchers, the attractiveness of male birds is tied to the length of their sperm.

The UK-based organization encourages public debate about the issue but does not recommend immediate policy change.

A small study based on circulating RNA in the blood of moms-to-be describes a technique that could be used to help predict who’s most at risk of preterm labor.