"It is an illness, either male or female factor infertility, and has to be treated like an illness, " she said.

BBC: ?1.5m to aid fertility services

Young, female teachers are also an important factor in attracting and keeping girls in school.

UNESCO: Dakar

Earlier research suggests that circulating levels of a potent stress hormone, corticosterone, in the female before conception or egg laying is a dominant factor.

MSN: Boy or girl? Moms have biggest say - Technology & science - Science - DiscoveryNews.com | NBC News

Akris's wind- and water-resistant textiles often emerge wrinkle-free from suitcases, and thus are a big factor in the label's success in catering to female executives.

WSJ: Polyester Is Back in Style at Alexander Wang, Talbot Runhof, Akris

Kim said her results didn't change with the child's birth order -- another possible allergy risk factor -- or if the child was male or female.

CNN: Where do allergies come from?

Managers should take note that "a raft of research published over the last decade has shown that gender diversity and the right balance of talent can be a contributing factor to business performance, so there is a strong business case to ensure that we nurture female talent from the very start of their careers", said Ms Jackson.

BBC: Graduate pay gap - women paid thousands less than men