Big apple vs. small
Women and men both have cartilage surrounding their voice boxes, but because men have bigger boxes (which give them deeper voices), their chunks of cartilage protrude more. This gives them neck lumps called Adam’s apples.
But why do men have deeper voices than women? The answer is that the pitch of a man’s voice match up with the amount of the male sex hormone testosterone he has, and his testosterone level is itself evocative of his genetic quality and sexual fitness. Because women have created to seek out men who have all the indicators of fitness and health, studies have shown time and time again that women tend to be more attracted to men with lower-pitched voices. They’re looking for a mate with whom to produce healthy offspring.