While many women believe that their husbands are pretending to be in deep sleep when the baby cries in the middle of the night, new research shows that men really just can't hear them.

According to a new study by the MindLab Institution, men are hardly disturbed by a baby's cries during their sleep, yet a wailing infant is the top sound that will take a woman out of dreamland.

Researchers believe it is women's maternal instincts -- whether they have children or not -- that kick in when they hear any young child cry that wakes them up.

Meanwhile, men are more likely to jump up at the ring of car alarms, a buzzing fly or howling wind. Men can also go right back to sleep after having been woken up much faster than women.

And it doesn't stop at men's and women's sleeping habits. Another study found that men and women respond to danger quite differently. Men are more likely to respond to stimuli that result in a physical reaction while women are affected more by things that are emotional, the radiology department at Jagiellonian University Hospital in Poland found.

In the study, men and women between the ages of 18 and 36 were shown a series of negative images and then another group saw positive ones. Their brain patterns showed that the men's autonomic nervous system -- which controls heart rate, breathing and even digestion -- was more reactive than the women's when negative images were shown.

So unless the baby cries during a symphony of car alarms while a fly buzzes past Dad's face as he dreams about getting into a bar fight, Mom will probably have to get up to feed the little one.