The sperm, belonging to a tiny marine crustacean, dates back nearly 100 million years, making it the most ancient animal sperm found to date.

In human male-female pairs with a less similar suite of genes for human leukocyte antigens, sperm fare better when exposed to cervical mucus.

Cellular innards can reorganize themselves to form structures similar to cells.

Proteins that synthesize, bind, and degrade endocannabinoids are present in the body’s sperm factories, suggesting that the use of cannabis may directly affect them.

Groups of corals release all of their eggs and sperm once a year, but the timing of their spawning is under threat from climate change.

Scientists track the movement of sperm flagella.

Asexual female nematodes use their male offsprings’ sperm to fertilize eggs, but cast away their genes.

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

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

The artificially motorized cells may one day help fight cancers in the female reproductive tract.

A project aims to preserve samples of the climate change–vulnerable animals for future restoration.

Mary Hagedorn is racing to save Earth’s coral reefs by developing techniques for freezing the colonial animals’ gametes.

New technologies reveal the dynamic changes in mouse and human embryos during the first week after fertilization.

The switch from maternal factors involves dynamic reprogramming of the zygotic genome.

Among their many functions, macrophages in mouse testes guard sperm against attacks by other immune cells. 

An app-based sperm analyzer screens for signs of male infertility.

The tails of polygamous deer mice sperm have longer midsections than the sperm tails of monogamous individuals of a similar species, and this correlates with improved swimming and competitive ability.

Murine embryos undergoing first cell division can reprogram injected sperm and develop normally.