Do Fathers Matter?: What Science Is Telling Us About the Parent We've Overlooked (9 page)

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The changes that occur in men during pregnancy have been observed by many others as well, confirming the reports from the Cowans’ families. During pregnancy, mothers experience a variety of profound hormonal and physical changes that help to prepare them for the substantial task of carrying and nurturing the fetus and new baby. That’s not news; what
is
news is that men also undergo hormonal turmoil. One of the most obvious changes is the weight gain that many men experience along with their wives during pregnancy. Many women experience cravings and of course require more food during pregnancy. The men’s weight gain could be occurring simply because they are tempted by all that extra food in the house. We don’t need hormones to explain that. Anthropologists have discovered that this phenomenon, called couvade (from the French word meaning “to hatch”), occurs not only in Britain and the United States but in non-Western societies, too, “sometimes to an even more extreme and incapacitating degree,” the Cowans write. In Papua New Guinea, some men, while waiting for their babies to be born, “retire to bed with unremitting nausea and incapacitating back problems, demand to be looked after, and otherwise raise an emotional fuss during the last months of their wives’ pregnancies.”

One of the key hormones that’s affected is the sex hormone testosterone. And the other is prolactin, a hormone involved in the production of milk by nursing mothers. Men have prolactin, too, even though they don’t nurse children. Why its levels should change in men has been a mystery. We’ve known that hormonal changes occurred in some animal species in which the fathers participated in rearing their offspring; prolactin levels rise in primates, in male birds just before they become parents, and in rodent species in which fathers help to care for their offspring. But nobody had shown much interest in looking at human fathers, to see whether something similar might be going on. In a paper published in 2000, Anne E. Storey, Katherine E. Wynne-Edwards, and their colleagues at Memorial University in Newfoundland began their study by acknowledging that lack of research: “Little is known about the physiological and behavioral changes that expectant fathers undergo prior to the birth of their babies,” they wrote. Based on the findings in animals, Storey and company predicted they would find similar changes in male humans, beginning during their partners’ pregnancy and continuing after birth. And they predicted that the variation in hormonal levels in any individual would be related to men’s symptoms during pregnancy and their responsiveness to their infants.

They recruited thirty-four couples taking prenatal classes at a nearby hospital and took blood samples from the men before and after the births of their babies. All but three of the couples were first-time parents. The couples were asked whether the men had experienced any of the typical symptoms of pregnancy—nausea, weight gain, fatigue, increased appetite, and emotional changes. The couples who were tested were exposed to their newborns, or to blankets that had been in the nursery, and to a film about breast-feeding to see whether the infant cues would cause any short-term change in hormone levels.

The tests revealed significant changes in each of the three hormones Storey and Wynne-Edwards measured—testosterone, cortisol, and prolactin. And the pattern in men was similar to what happens in pregnant women. Men’s testosterone levels fell 33 percent when they had their first contact with their babies, compared to measurements taken near the end of their wives’ pregnancies.

What could explain this change in testosterone? Many scientists believe that a rise in testosterone is associated with competitive behavior in animals and in men. The drop that occurs with the birth of a baby might be nature’s way of encouraging men to drop their fists, at least temporarily, and nuzzle their babies. From an evolutionary perspective, this is smart. Competitiveness is incompatible with nurturing. And men who are more bonded to their babies are more likely to stick around and support them.

Indeed, in September 2013, James K. Rilling and his colleagues at Emory University reported in the
Proceedings of the National Academy of Sciences
that testosterone levels in the blood were inversely correlated with paternal caregiving—that is, testosterone was highest in fathers who devoted less effort to child care, and lowest in those who invested more effort in child care. They also found that the fathers who devoted more resources to their children had smaller testicles. The results provide evidence for the supposition that there is a trade-off between the effort devoted to mating and to parenting. Some males choose to devote more effort to mating and less to child care; others choose the opposite course.

This relationship is seen in animals. Male chimps, who are sexually promiscuous, have testes twice as big as those of humans on average, and they generally don’t provide much paternal care. Gorilla males have small testes and guard their young. Human males vary from one individual to another in which approach they are more likely to follow. Rilling’s aim with this study was to try to explain why some men are better fathers than others. And while the study doesn’t prove that large testicles and elevated testosterone levels can predict what kind of father a man is going to be, it is an important step toward a better understanding of why men vary so widely in the effort they devote to caring for their children.

Storey and her team, in their research on hormonal changes, found other changes in men during their partners’ pregnancies—notably, a rise in prolactin near the end of pregnancy. Levels of prolactin were higher in men who showed greater responsiveness to their babies’ cries and in men who showed more pregnancy-related symptoms. And there was a clear link between women’s hormone levels and those of their partners. Women’s hormones rose and fell in connection with the physiological process occurring during pregnancy. Men’s hormones rose and fell in accordance with the hormonal changes in their partners.

Women’s hormonal changes during pregnancy varied as the time of birth approached. Their hormone levels are associated with the changes going on in their bodies during pregnancy, of course. But fathers’ hormonal changes did not correlate with the number of days until birth—they correlated with the hormonal changes in their female partners. This all pointed to the conclusion that the closer and more intimate partners are during pregnancy, the more the man’s hormonal shifts parallel those of his partner—and the better a father he becomes.

While this doesn’t
prove
a connection between maternal and paternal hormones, it strongly suggests that there is a link, and that these hormonal changes are important for the development of nurturing fathers. Indeed, further research by Storey and Wynne-Edwards has shown that expectant and new fathers who hold their baby—or even a doll wrapped in a blanket that smells of their baby—experience a rise in prolactin and cortisol and a drop in testosterone. The hormones seem to be powerful drivers of men’s behavior during pregnancy. It’s astonishing that, as far as we can tell, men are mostly unaware of these changes in behavior.

More than hormones are at work, however, in shaping men’s relationships with their infants. A father’s physical and mental status can also affect an infant’s health. In 2010, Prakesh S. Shah of the University of Toronto noted that scant research had been done on whether there was any link between fathers and either preterm infants or those born full-term with low birth weight. (Both outcomes increase the risk of illness or death in the first days and weeks of life.) Most research had been done on mothers, as you might expect, where the possibility of a link between the mother’s adverse health or behavior and her infant’s outcome might be easier to understand. Mothers’ risk factors for adverse outcomes have been studied extensively, for the obvious reason that mothers contribute far more to their children during the nine months of gestation than fathers do. That’s a fact of biology. But that doesn’t mean fathers should be overlooked.

To remedy the lack of information on fathers, Shah and his colleagues collected thirty-six studies and analyzed them to see what links they might reveal between fathers and birth outcomes. They concluded that these adverse outcomes in babies were more likely to occur as fathers grew older and if the fathers had been born with low birth weight themselves.

The Toronto study was accompanied by a commentary in the same issue of the
American Journal of Obstetrics and Gynecology
, in which another group of researchers criticized the team for not going further. The critics said the scientists had failed to consider a long list of paternal factors that could influence birth outcomes. These include how fathers feel about the pregnancy, their behavior during the pregnancy, and their relationships with the mothers. All of these circumstances can increase mothers’ stress during their pregnancies and affect how well they take care of themselves. When fathers don’t want to have the baby, mothers are less likely to get prenatal care. Cigarette smoking by fathers can influence a mother’s decisions regarding smoking and increase the likelihood of low birth weight.

The commentary marked a rare instance of researchers being publicly criticized for failing to give fathers greater consideration in research. It ended with a recommendation that doctors and scientists devote more attention to fathers when assessing pregnancy risks. It’s a good sign: attitudes are changing.

An example of the kind of research the critics were advocating has come out of a group at the University of South Florida led by Amina Alio, a professor of community and public health. She and her colleagues found that fathers who were involved with their partners during pregnancy reduced the risk that the children would die in the first year of life. Infants whose fathers were absent—and had no involvement in the pregnancy—were more likely to be born with lower birth weight and to be born prematurely. The death rate of infants whose fathers were not around was nearly four times that of infants whose fathers
were
involved. And many maternal complications that could affect the infants—such as anemia, high blood pressure, and more serious ailments—were more prevalent among women whose children’s fathers were absent.

Yet another study out of New Zealand in 2011 looked at how fathers could affect the birth weight of their children. The group recruited 2,002 couples while the women were pregnant and followed them until birth. Was there a connection, they wondered, between obesity or blood pressure in fathers and the size of their children? Nothing appeared to link blood pressure to birth weight, but something quite startling appeared when they looked at fathers’ weight: obesity in fathers, and what’s called central obesity, or abdominal fat, were each associated with a 60 percent increase in the risk of having a child with a low birth weight. It didn’t matter whether the mother was obese.

This was a revelation. Once fathers have fertilized an egg, they have no physiological connection with their developing fetuses. But somehow they
are
affecting the children’s physiology. How does this happen? One guess is that mothers and fathers tend to eat similar diets, and so a father’s overeating could influence his partner. Another is that somehow the father’s genes are influencing the baby’s growth in utero—exactly how that might happen is not known. These discoveries posed yet another challenge to the exclusive research focus on mothers. No one had seen the importance of fathers during pregnancy because investigators had never looked for it.

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The new understanding of the biology of fatherhood posed a serious challenge to the mainstream psychological beliefs of the twentieth century. Those beliefs were shaped largely by John Bowlby, who developed one of the most influential and widely accepted psychological descriptions of human development: attachment theory. This grand idea said that an infant’s attachment with one caregiver—the mother in almost all cases—was essential for normal psychological growth.

Bowlby began his work in the 1940s. At the time, one of the leading figures in the psychology of parenting was John Watson, who accused parents of being “mawkish” and “sentimental” in their treatment of their children and counseled stern parenting. It’s a bad idea to pick up a crying baby, he warned, because that encourages the child to cry more. It was far better to let the baby cry it out. Bowlby’s attachment theory drove Watson to the sidelines. Unlike Watson, who thought crying should be discouraged, Bowlby thought it was natural, a kind of protective alarm engineered by natural selection. Babies cry when they need help, food, or protection.

Despite his influence, Bowlby never achieved the popular recognition of his more famous predecessor, Sigmund Freud. Freud was not a scientist, although that’s the way he thought of himself. He was a brilliant writer and theorist, but his observations were limited to a very small group of people, almost all of whom came to his attention because they were suffering from a psychiatric disorder. But the timing had been right for Freud’s ascendance. Darwin had sought to explain much of biology with simple biological principles, and Freud was trying to do the same thing with human behavior. By the 1950s, nearly every prestigious department of psychiatry in the country was led by a Freudian analyst. They wrote the textbooks, ran the journals, and called the shots.

That’s roughly when Bowlby came along to challenge Freud’s supremacy. Unlike Freud, Bowlby was a scientist who engaged in conventional research. One of his first projects was a study intended to find out why some children formed secure attachments to their mothers while others didn’t. He collaborated with ethologists who were studying parental attachment in animals, to see whether that could shed any light on human attachment. He drew on evolutionary biology, seeking to learn how attachment might affect the likelihood of survival for an animal or a child. And he observed that children who had formed close attachments to their mothers before the age of two were more confident about exploring the world around them, while those who had not were more passive and more likely to cling to their mothers. Children who did not form such secure relationships were likely to suffer from separation anxiety for years to come.