I know that there are going to be a ton of exceptions, but I was extremely interested to see a study in the journal Biology Letters that seems to indicate that a deep male voice may attract women more than a great physique or an attractive face. Men with deep voices are also much more likely to have more children than men who do not have deep voices.
The investigators used an interesting analogy, sating that a man's deep voice is a bit like a peacock's tail: it has no survival value, but attracts the female of the species. Testosterone masculinizes the voice at puberty.
The research team interviewed 52 women and 49 men aged 18-55, from the Swahili–speaking Hadza tribe in Tanzania. They chose the Hadza tribe because their lifestyles reflect those of our hunter-gatherer ancestors. The females gather berries and search for wild plants. The males collect honey and hunt animals. Even though the Hadza are monogamous, extra-marital sex is common, but there is no birth control.
During the interviews, which took place in Swahili, the voices of the men and women were recorded. On studying the recording later they found that the deep voiced men had fathered more children than the non-deep voiced men. The man with the deepest voice had ten surviving children, while the one with the highest pitched voice had three.
Coren Apicella, the lead author, suggested that perhaps the males with the lower pitched voices had higher testosterone levels, which attracted them more to females or made them more attractive to them. It is also possible that men with higher testosterone levels start reproducing earlier in life. They may also be better hunters, since testosterone may have an impact on muscle mass, and a better hunter would bring more food, allowing their wives to have shorter inter-birth intervals.
It is possible that if vocal dimorphism evolved partly due to mate selection, then in the past men and women may have had more similar voices.
I don’t suppose that anyone is going to be too interested to hear this, but your humble reporter has always had a very deep voice…