It is a reality, and it is not fair: if you leave the workforce for a period of time, even for a good reason, your career can suffer for decades to come. Women have known that for a long time though the ‘motherhood penalty’ on earnings that results from choosing to stay hone with their children even temporarily. Now, men are apparently facing that same reality.

According to this piece from Bloomberg, men are dropping out of the U.S. labor force in significant numbers. The male participation rate – the proportion of those in the working age population who are either working or looking for work – is now 88.4 percent, down from 97.9 percent in 1954. So basically the U.S. has gone from a time when men just worked, period, to one where a solid percentage do not.

The big change to participation between 1954 and 1997 comes not from early retirements, but from a move for those aged from 25 to 34 to leave the labor force. Some of this group are clearly in school, and to be sure getting a MBA or whatever will likely pay off for them in the longer run. What the U.S. figures show, however, is that many of the out-of-workforce men are not actually pursuing an education. In fact, a chunk are veterans getting some kind of disability benefits, and yes, some are stay at home dads.

It is that increase in stay at home dads that I find interesting. According to the Pew Research Institute, the number of stay at home dads in the U.S. hit 2 million in 2012, up from 1.1 million in 1989. On a percentage basis, the U.S. Bureau of Labor Statistics estimates that 7.8 percent of U.S. families had only the wife employed in 2013, up from 5.7 percent in 1994.

I think that having dad stay at home is a great option for families if they decide that works for them, just as I think it is a great option if moms decide to do that However, I would be fearful for any young woman who decided to stay at home and in the process became viewed as unemployable, meaning she could not earn a living should she need to. I have the same fears for young men. The women at least are likely to have left jobs in the service industries or the public sector, and may be able to pick them up later. Disproportionately, the men would have left manufacturing or construction jobs that have disappeared all together. Without specific re-training, their re-entry into the workforce will be that much harder.

Given the fact that young women are earning more college degrees than men and are finding their way up the ladder in many careers, the decades ahead will undoubtedly see many families find it makes more sense for dad to stay home. Those dads who do not want to stay home long term would be best to prepare for what comes next and be ready to accept lower wages than they remember when they do go back to (the other kind) of work.