a new study in the psychological journal Emotion claims that "baby fever" -- that sudden, visceral, and almost irresistible urge to have a baby -- not only exists, it can be found in both men and women.
"Women reported that it happened more frequently and more strongly but it's there for both men and women," says Gary Brase, associate professor of psychology at Kansas State University who along with his wife Sandra Brase, spent nearly 10 years studying the phenomenon.
The researchers, who have two children, first looked at three theoretical viewpoints as to why baby fever might exist and where it could come from. One theory had to do with gender roles, i.e., women think they should have kids because that's what they're taught women are supposed to do. A second theory had to do with nurturing.
"Humans are biological organisms, we have a sex drive and we nurture once a child is born," says Brase. "We looked at whether baby fever was due to people looking at someone else's child and then having that trigger misplaced nurturance. But it wasn't that either."
A third theory had to do with timing -- the brain delivering a signal that this could be a good time to have a child. But when they talked to their test subjects (a total of 337 undergrad students and 853 general population participants gathered via the Web), none of these theories seemed to hold up.
Instead, three factors consistently predicted how much a person wanted to have a baby.
"The first two had to do with the visual sensory things," says Brase. "Seeing a baby, hearing a baby, smelling a baby led some people to want to have a baby." [...] A third factor had to do with trade-offs that come with having children. - Source
Anna Rotkirch, the director of the Population Research Institute in Finland, says studies have shown “the urge appears to be strongest in the late 20s.” [...] Rotkirch reported in a paper in the Journal of Evolutionary Psychology that her Finnish interview subjects described the phenomenon in terms of “a painful longing in my whole being” or an “unbelievable aching,” sometimes accompanied by the sensation of having “empty arms” or breasts that “became sensitive and hard.” In a related survey, she found that 58 percent of male respondents and 78 percent of female respondents reported having “experienced a strong desire to have a child of [their] own” — although this seems less a measure of sudden, acute longing than of a general desire to reproduce at some time. [...] “All existing studies use written texts or questionnaires,” she says, which tell us more about how women perceive their “baby lust” rather than the actual origins. Still, Rotkirch has found evidence of a “hormonal underpinning,” she says, with “little influence” of social factors like education or income.
In her paper, she pointed out that, in terms of evolutionary biology, “the ‘default mode’ of the female body is to have experienced both nurturing and pregnancies by the early 20s.” Rotkirch suggested that “longing for a baby can develop as a by-product of hormonal changes that evolved to prepare the woman for motherhood,” she wrote. “Such changes could be induced by falling in love; the ‘nesting behavior’ related to settling down and starting to live with a partner; exposure to infants; and/or by the processes of aging.”
If evolutionary theories are too caveman-y for your taste, there is the undeniable fact that women’s fertility begins to decline in their late 20s, right around the average time that baby panic sets in. She says, “My informed guess is that baby fever is one mechanism for reproductive timing” — or, in other words, a way to urge that “now is a good time to have a baby.” It seems to make intuitive sense, but the science on exactly how this mechanism might work is just not there.
[...] In an exhaustive study surveying the potential causes of the phenomenon, Gary Brase, an associate professor of psychology at Kansas State University, found that men experience it, just to a lesser degree than women do.
[...] Brase, who has studied the issue for nearly a decade, found that beliefs about gender roles — for example, a woman’s conviction that her proper place is in the home — were not strong predictors of baby fever. “Desire for a baby is not strongly connected to people’s gender roles,” he told me.- Source
The study linked from the above:
ALL THAT SHE WANTS IS A(NOTHER) BABY? LONGING FOR CHILDREN AS A FERTILITY INCENTIVE OF GROWING IMPORTANCE - A. ROTKIRCH - Institute for Population Research, Family Federation of Finland - 2007
Abstract. The article discusses the existence and outlook of an evolved desire to have children. Twin studies have found a genetic basis for conscious attempts to get pregnant. This heritable disposition increasingly affects societies of wide female reproductive choice (KOHLERet al 1999). Based on 106 stories written by Finnish women in2006, I analyse the symptoms, triggers and behaviour related to longing for babies. I suggest that a strong longing for first or subsequent children is an affective incentive of growing importance in low-fertility societies. Female desire for babies appears in two main forms: as part of a generally care-oriented personality and as a sudden, surprising and largely physical longing. The first type conforms to previous research on nurturing (MILLER1986; FOSTER2000) while the second type has not been much studied yet. For both types, a desire to have children is often related to physical age, falling in love, previous pregnancies and to exposure to babies of kin and peers. I discuss evolutionary explanations and suggest that longing for babies may have evolved not only as a by-product of finding care pleasurable, but also as part of mate selection and as a consequence of hormonal changes induced by couple formation and ageing.
Table 1: “Have you felt a strong wish to have your own child (‘baby fever’)?” Finland 2007, by age and gender, N = 1560 (%, n) Women Men No 21.7 42.4 Yes, once 49.8 44.9 or a few times Yes, often 28.5 12.7