Paid maternal leave is usually based on short-term disability insurance, essentially treating pregnancy as an illness or disability; one that men obviously cannot suffer.

However, there are some concerns about whether women-specific leave enshrines gender inequities more than it combats them. A policy that only allows mothers to take time off to care for a child is likely to cement her as the chief caretaker and likely lead to an uneven division of childcare in the household.

In addition, if only women enjoy the prospect of taking significant time off to care for a child, then employers may be reluctant to hire women of child-bearing age.

Discrimination against female applicants has emerged as a challenge in some European countries where employers have long-been mandated to provide women with substantial paid time off following a pregnancy. Some countries, such as Norway, have responded by allocating leave to a child's parents, who are allowed to split it, so that the father and mother take the same amount of leave.

"We should structure policies assuming that men want to fully participate. In fact, we should structure policies to encourage that they do," Ellen Bravo, co-founder of Family Values @ Work, tells the Wall Street Journal.

The move towards gender-neutral parental leave is only just beginning. While 58 percent of employers offer some type of paid maternity leave, only 15 percent have a policy in place for fathers.