Hearing an infant cry may spur the release of additional testosterone in men, a new study finds.

“Hormones and behaviors are linked in dynamic and complex ways, more complex that we often think,” says study researcher Sari van Anders, a behavioral neuroendocrinologist at the University of Michigan.

But research has largely shown that parenting is related to lower testosterone levels in men.

“This completely contradicts theory and the larger body of evidence,” van Anders said.

In the study, college-age men who were unsuccessful in their attempts to comfort crying dolls had no testosterone change; those whose comfort was successful had lowered testosterone rates; and those who were unable to respond to the crying had increased testosterone levels.

Testosterone may be stimulated in cases where an upset baby may indicate a danger or emergency response to infant protection, van Anders theorized.