To be enamored or in love may cause changes in men and women's testosterone levels.
An Italian study suggests that when couples fall in love their testosterone levels alter. An equilibrium occurs whereby testosterone decreases in men and increases in women so they become more alike.
"Men who were in love had lower levels of the male sex hormone testosterone than men unlucky in love," New Scientist magazine said on Wednesday.
"Love-struck women, in contrast, had higher levels of testosterone than their counterparts."
Donatella Marazziti, a scientist at the University of Pisa in Italy, made the discovery after studying 12 couples in love.
"It's as if nature wants to eliminate what can be different in men and women, because it's important to survive at this stage," she said.
Two years later, when the same people were tested again and were no longer madly in love, their testosterone levels were back to normal.
Testosterone is a principal male sex hormone. Though this hormone normally (and necessarily) occurs in small amounts in females, it is chiefly known as the hormone responsible for stimulating the development of male sex organs and male secondary sexual characteristics, e.g. facial hair, deepening of the voice, and muscle development.
Love after all may be good for the heart as this recent related study suggested
Having a really close relationship with another person, whether it be friend, lover, or relative, can halve the risk of further heart attacks.