> A new study could change that. Researchers have identified an odorless compound emitted by people—and in particular babies—called hexadecanal, or HEX, that appears to foster aggressive behavior in women and blunt it in men.

Hexadecanal is a sixteen-carbon chain aldehyde:

https://en.wikipedia.org/wiki/Hexadecanal

A few years back a team claimed to have isolated essence of old person, 2-nonenal, a chemically-related nine-carbon unsaturated aldehyde:

https://en.wikipedia.org/wiki/2-Nonenal

https://www.jidonline.org/article/S0022-202X(15)41198-4/full...

The occurrence of pheromones in the animal kingdom, but so far scant evidence in humans, is a puzzle:

https://www.scientificamerican.com/article/are-human-pheromo...

Maybe there really are no human pheromones. Or maybe they're just really hard to study because studying human behavior is so hard in general.