Form and Function

Canadian Public Radio to the rescue again with a show on how humans use smell to pick their mates. The research started out with a group of men each wearing the same shirt overnight for two nights and then having women smell the shirts in a lab and report how appealing they found the smell of each shirt. (Hopefully the women were receiving some sort of stipend for their part in this.) The results indicated that women prefer the smell of men who are genetically dissimilar to themselves in the area of MHC genes. (Whether this "MHC" is the same as the "MHC" of "Major Histocompatibility Complex" they never said, but I'm guessing yes because the result of previous studies mating animals with dissimilar MHC genes resulted in offspring with stronger immune systems.) Women have also been found to find men who are MHC-dissimilar from themselves to be more sexually attractive. Interestingly, women who were on the Pill at the time of the trial tended to select the smell of MHC-similar men as being the most appealing. The researchers' theory as to why this may be is that while MHC-dissimilarity is most beneficial for health of offspring, consistent material support (e.g. food and shelter) during pregnancy and childrearing is also important; because the Pill induces a hormonal state similar to pregnancy, it may be that those women on the Pill were more likely to choose MHC-similar men, such as would occur with a closer genetic relative, as an evolutionary bet on receiving more "familial"-type assistance with childrearing.

Quirks and Quarks can be found here. The episode "Sniffing for Sex" is here.