But there is overwhelming evidence that some smells affect our behavior profoundly. The most famous example is probably the research of Martha McClintock of the University of Chicago. In her 1971 paper in the journal Nature, she argued that women’s menstrual cycles become synchronized when they live in proximity, and that this is due to unconscious odor cues, or pheromones.
Several other studies also suggest that pheromones are at work on a daily basis in people. For example women tend to prefer the smell of sweat-drenched T-shirts from men who differ from them in an important set of immunity genes. The theory is that such opposites-attract pairs would have kids with particularly diverse, and hence well-armed, immune systems.
An interview with Lisa Jean Moore, author of Sperm Counts: Overcome by Man's Most Precious Fluid:
In the book, you tie sperm technologies, like sperm banking and artificial insemination, to a crisis of masculinity. How have these technological changes affected the way that men see themselves?
I want to be careful. I don't want to make it sound like average men are aware of all the technical things that are happening to their physical capabilities. I think it's more of a long-term process that I'm proposing as a theory.
Technology has made sperm so pliable, so knowable, something that can be so sterilized, and so flexibly used, that women can now begin to use it. It can be extracted from male bodies and men can be bypassed in the process of reproduction. [Having] semen available in a marketplace radically changes the definitions of paternity, paternalism and fatherhood, and the fatherhood rights movement is reacting to that. It's finding that incredibly threatening to their ability to maintain notions about the heterosexual-male-dominated family.