Butterflies exhibit striking differences between males and females, a phenomenon called sexual dimorphism. These variations, ...

Researchers who analyzed data from zoo animals found that it is not only genetics, but mating pressures that may determine ...

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In mosquitofish, of the genus Gambusia, male fish are smaller than females -- sometimes only half the size. Biologists had previously assumed that smaller male mosquitofish had at least some ...

Women usually live longer than men, and animals show the same pattern. Evolution, genes, and parenting explain why.

A lower percentage of males improves mating behaviour and feather cover, with similar reproduction results and higher ...

The coronavirus disease 2019 (COVID-19) outbreak caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was declared to be a global pandemic by the World Health Organization (WHO) on ...

Intersex is an umbrella term for people who are born with one or more traits in their chromosomes, genitals, hormones, or internal reproductive organs that don’t fit the typical male or female ...