The Male Brain by Louann Brizendine

words his older brother Mike had said were haunting him: "Fatherhood changes your life forever, dude."
    Mike was right. Some men are over the moon about their wife's pregnancies, but studies show that feelings of distress peak for most men four to six weeks after they discover they're going to be fathers . They seldom reveal these worries to their mates, and Tim's way to handle anxiety about being a father turned out to be by arming himself with information. He asked me to suggest some books on pregnancy, childbirth, and parenting. He also went online for information, and it turned out that some of what he read just raised more fears. For example: "The way parents tend to a baby's needs during the first weeks and months after birth can shape the baby's brain for the rest of its life ." By the time Michelle had her three-month prenatal visit, Tim's nerves were more jangled, not less.
    The turn for the better came when Michelle lay on the table for her first ultrasound. Tim was sitting alongside her as the doctor rubbed cold gel on her belly and turned on the machine. When a baby's image appeared on the screen, Tim audibly gasped as he saw its heart beating. "It was like nothing else mattered," he said. "All I could do was stare at this tiny beating heart and think, 'Oh my god, that's my child.'"
    Scientists now know that a man's brain changes as his mate's pregnancy progresses. Dads typically don't crave pickles with ice cream or wake up nauseated every morning as moms do, but they do have emotional, physical, and hormonal shifts in parallel with their mates' pregnancies. Research at Harvard University revealed that two major hormones change in fathers-to-be: testosterone goes down and prolactin goes up . Scientists believe that men may be responding to the natural airborne chemicals of pregnancy--pheromones--emanating from the mother-to-be's skin and sweat glands . Unbeknownst to him, these hormones are priming him for paternal behavior. In some men, this hormonal shift can cause couvade syndrome--" sympathetic pregnancy ." Couvade syndrome has been documented in fathers-to-be worldwide, and Tim was experiencing it firsthand. By the beginning of Michelle's second trimester, she needed bigger clothes--and so did Tim. He'd gained fifteen pounds.
    And in a biological tit for tat, at least in mice, the father's pheromones have been found to waft through the air and into the mother's nose and trigger her to make more prolactin, a hormone that increases the growth of maternal brain circuits . The mommy brain begets the daddy brain, and the daddy brain abets the mommy brain.
    As Michelle's belly and due date loomed large, she spent hours refolding tiny baby clothes and blankets and collecting all the other baby supplies she thought they'd need. Meanwhile, Tim was also "nesting." He became obsessed with fixing up the house, painting the baby's room and building shelves for all the new infant equipment, books, and toys. Scientists have found that men have the biggest hormonal leap from non-dad to dad in the days leading up to the birth. Researchers studied fathers-to-be during the last trimester of their wife's pregnancy and found that these men's prolactin levels increased by over 20 percent and their testosterone dropped 33 percent during the three weeks before birth . And by the time their children were born, not only had the fathers' testosterone dropped, but they were better at hearing and emotionally responding to crying babies than non-dads were. On average, a man's testosterone and prolactin levels will begin to readjust when the baby is six weeks old, returning to prefatherhood levels by the time the baby is walking.
In cultures around the world there is a lot of variability among fathers. Dads who are actively involved in taking care of their children have been found to have lower levels of testosterone Researchers compared cultures, one in which fathers give a lot of hands-on care and another in which fathers give very