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

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.

Bigger, older mothers produce disproportionately more eggs than their smaller counterparts do.

Cuckoo catfish trick cichlids into caring for their eggs in a strategy known as brood parasitism.

The reproductive biologist uncovered hormones important for fertility cycles.

The alterations have been greater under rapidly-climbing global temperatures, suggesting key ecological relationships could be disrupted in the future.

The variation may help explain why stocked salmon don’t fare as well in the ocean.

The goal is to house patients’ follicles in a specially designed tissue matrix and reinsert them after treatment.

A fruit fly ovary can contain up to 20 eggs at a time.