Recent research suggests that well-fed males who gain weight quickly as babies grow taller and end up having more sexual partners.
Previously researchers had known that all male newborns get a surge of adult-strength testosterone for a brief period.
Researchers examined nearly 800 Filipino men from birth to between the ages of 20 and 22.
They found that men who were well fed-and thus gained weight faster-as infants reached puberty earlier, started having sex earlier, and had more sex partners over their lifetimes.
Men who'd grown fast as babies had an average of 3.2 sexual partners by the time of the 2005 survey, while those who'd grown slowly had an average of 1.7 sexual partners.
The faster-growing men also had more testosterone, were taller and more muscular, and had a stronger grip, among other factors.
The approximately 700 women tested in the study, who do not have an early spike in testosterone, did not show a link between fast infant growth and an earlier onset of puberty.
"Our study provides additional evidence that our fates are not hardwired at birth," National Geographic News quoted study author Christopher Kuzawaof Northwestern University as saying.
"We can't rule out genetic contributions, [but] I think we have good evidence that it's not simply a genetic story."
Kuzawa's hypothesizes was that the body can "sense" nutritional status early in life and adjust accordingly. When food is abundant, a male can afford to build a beefier body. But in an environment where food is scarce, it "pays to be smaller," said Kuzawa.
Kuzawa cautioned that this study is the first time a link has been found between nutrition and early puberty, which means it's too early to extend the findings to babies in other countries.
The study appeared in the journal Proceedings of the National Academy of Sciences.