Whether or not individuals want a boy or girl comes down to one main factor: their own sex. That's according to a new study which found that men tend to want sons while women have a stronger preference for daughters.
It was a surprising outcome for the researchers who expected to find a link between preference for a particular gender and a range of other factors - but didn't.
"Our study failed to show that the parents' preferences for the offspring's gender are affected by their status, wealth, education or childhood environment. Instead, parental preferences were best predicted by their sex," said lead author Robert Lynch from the University of Turku, Finland of their findings.
"Women from all socioeconomic backgrounds expressed implicit and explicit preferences for daughters: they chose to donate more to charities supporting girls and preferred to adopt girls. In contrast, men expressed consistent, albeit weaker, preferences for sons."
As part of the study, published in the journal Scientific Reports, researchers recruited a group of 770 participants. They were asked to complete a number of tasks, which included answering the question: "If you could choose the number and sex of all of the children you will have in your lifetime: How many boys would you want?— and How many girls would you want?—"
- Answered a question about whether they wanted to donate some of their fee for doing the study to a charity benefiting either girls or boys
- Answered a hypothetical question about adoption: "Imagine that you and your partner want to adopt a child. You visit an orphanage and pay the adoption fee. The orphanage only allows couples to adopt one child. You are given the choice of fraternal (non-identical) twins, one boy and one girl. Both are 12 months old. Whom do you choose to adopt?"
- Completed an implicit task about gender, designed to capture more automatic responses to gender preferences than than self-reporting.
"Female participants showed a strong preference for adopting girls, donated far more to charities supporting girls rather than boys, scored much lower on the Implicit Association Test (i.e. implicit preference for girls), and preferred female-biased offspring sex ratios," the authors write.
"Males, meanwhile, showed no significant preference for adopting daughters vs. sons, a modest preference for donating to charities supporting girls, a slight implicit preference for boys and a slight explicit preference for a male-biased offspring sex ratio."
So why might that be the case? The authors suggest a number of theories.
"Parental investment patterns have been changing rapidly in developed countries like the United States over the past few decades and some evidence indicates that, overall, parents now invest more in daughters than they do in sons," they write, adding that prospective couples are 45 per cent more likely to express an interest in adopting daughters over sons.
"Therefore these results showing overall preferences for daughters may reflect the cultural impact of parental sensitivity to increasing economic prospects for females in Western, industrial societies."
Better ... ahem ... return on investment:
"Because in the United States girls outperform boys in school and are far more likely to attend college, the expected return on investment for daughters is rapidly increasing, which may account for the overall girl preference in our sample," the authors note.
That said, the researchers do acknowledge that findings in the area are mixed - and their results may not be relevant for individuals outside the Finnish sample they studied.
"There is some evidence that, although overall parents tend to express preferences for their same sex offspring, fathers are increasingly likely to prefer daughters as genders roles have changed (e.g., girls are increasingly more likely to play sports)," they write.
A study published in 2012 in Open Anthropology also found that women want girls and men want boys. Rather than a better return on investment, however, the authors speculated that women want daughters so as to leave a legacy - a "close copy" of themselves. For women, the desire for a daughter was extremely strong, especially in the scenario of an only child.
But what of men wanting sons? Blame it on the patriarchy. "[Men's desire for male bubs] represents a lingering remnant of the long history of widespread patriarchal dominance in human societies – with its evolutionary roots signalled in the present data by a persistent and conspicuous male preference for sons," the authors said.
A recent study published in Social Science and Medicine found that women who gave birth to boys were significantly more likely to experience post natal depression. And while increased inflammation might be to blame (analysis of placental tissue indicates that mums produce a stronger inflammatory response to boy babies), the authors also noted that an "undocumented preference for daughters" in other words, gender disappointment, could also be behind their findings.