Lady Pigeons’ Hormones Show the Value of Studying Both Sexes

This just in: Organisms of different sexes have different physiology. It’s a wild idea, we know, but hear us out. A new report on pigeon hormones in the journal Scientific Reports refutes the longstanding scientific assumption that studying female organisms is a waste of time.

This is not an exaggeration. "There's a problem of sex and gender inclusion at all levels of science from faculty to the animals we use," senior author Rebecca Calisi of the University of California, Davis said in a statement.

Until quite recently, it was standard practice for researchers to use mostly or exclusively male organisms, from cells in petri dishes all the way up to patients in clinical trials. Scientific institutions working to correct this extremely un-scientific imbalance have been met with resistance, as some researchers continue to argue that including females is complicated, expensive, and redundant, as male organisms are surely a good-enough stand-in for an entire species.

Little by little, small experiments and large-scale studies are chipping away at these arguments. The latest evidence in support of balanced research practices comes from Calisi and her colleagues at UC Davis and the University of New Hampshire.

Calisi and her colleagues examined the genes of 24 pigeons (14 male and 10 female), focusing on the expression of genes in each bird’s hypothalamus, pituitary gland, and reproductive organs.

Gregory Urquiaga/UC Davis

They found differences between male and female birds. A lot of differences. Hundreds, in fact.

“There are incredible differences in gene expression, especially in the pituitary," Calisi said.

She and her colleagues were restrained in summarizing the significance of their findings, noting simply that “[Their] results highlight the need for sex parity in transcriptomic studies, providing new lines of investigation of the mechanisms of reproductive function.”