Roughly 1 percent of moms may be virgins -- or so they claim in a new survey.

Virgin birth, or parthenogenesis, typically occurs in non-humans that reproduce asexually, including sharks, Komodo dragons, pit vipers and boa constrictors. The British Medical Journal, which published the study in its latest Christmas issue, points out many retell the birth of Jesus to the Virgin Mary this time of year.

A team of American researchers wanted to find out the frequency this occurred in humans.

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“We examined the incidence of virgin pregnancy and birth based on self report of pregnancy and sexual debut, hypothesizing that individual and contextual factors may influence reporting,” wrote the researchers, led by Amy H. Herring, a biostatiscian at UNC’s Gillings School of Global Public Health.

Indeed, that appeared to be the case for some women. The researchers found 0.8 percent of responders gave birth despite being virgins, without the use of any assisted reproductive technology like IVF.

These women were more likely to have signed chastity pledges (31 percent of them) than the non-virgins who reported pregnancies (15 percent).

For the study, researchers surveyed data on almost 7,900 women multiple times over a 14-year period between their adolescent and adult years, each time asking about their sexual and pregnancy histories. They were also asked about their age, religion and knowledge of different birth control methods.

In total, 45 women gave birth while consistently claiming they were virgins. Sixty percent of them gave birth to boys or found out they were pregnant during Advent, the period before Christmas when Christian observers prepare themselves for the birth of Jesus. However, that number was not statically significant, meaning the probability of that happening may have been due to chance.

Virgins were typically younger at the time they gave birth -- an average of 19 years -- than non-virgins, who were around 22 years old. These women were more likely than non-virgins to have parents who didn’t speak about sex and birth control with their child, the survey also found.

The study also recorded data on virgin women who have yet to give birth, and found perceived importance of religion was associated with virginity but not with virgin pregnancy.

The researchers used top technology for computer-assisted self interviews, though they concede most times in surveys, there is room for respondent bias and misclassification. In other words, these women may not have been virgins after all.

“Numerous important factors can be only feasibly or affordably measured in large samples using self report in surveys, including sexual history, illicit drug use, domestic violence, maltreatment as a child, and diet,” they wrote. “Unfortunately this means there is no ideal against which to judge accuracy of self report.”

The study was published in BMJ’s annual Christmas issue, where researchers publish well-designed, atypical research papers that reach eyebrow-raising conclusions.

Last week, BMJ published a study in which researchers examined the drinking habits of famed fictional spy James Bond. The researchers concluded his alcohol intake likely would have put him over the legal limit before his car chases, and led to alcohol-induced brain damage, erectile dysfunction and an early grave.

In recent years, the issue has tackled the speed of the Grim Reaper and the case of the rogue tooth fairy may have committed malpractice after the tooth ended up in a boy’s ear canal.

The full study, “Like a virgin (mother): analysis of data from a longitudinal, US population representative sample survey,” can be accessed on BMJ’s website.

