CommentaryWhile U.S. vehicle manufacturers wring their hands over escalating health-care costs, an auto workers’ union half way around the world has a new proposal that surely has feminists wondering where they went wrong.

The Australian Mfg. Workers Union is asking for 12 days paid menstrual leave each year for women workers at Toyota’s vehicle production plant in Melbourne. The request is being rolled into bargaining for a new 3-year contract with the auto maker that covers about 4,000 workers, up to 12%, or about 480, of them women.

The provision would be in addition to the established sick leave for all union workers.

A union executive says providing female auto workers with paid menstrual leave would improve the company’s productivity and quality. Production line jobs are tough on some women during their monthly cycle, he says, and their problems should be recognized.

It is likely that out of 600 union demands for the new contract, this nod to women workers is more of a bargaining chip than a serious issue. But suppose for a moment that such a movement were to catch on.

Although it’s true there are gender-specific issues that companies must deal with, such as maternity leave, time off for monthly menses appears to create more problems than it solves. For one thing, it erodes hard-fought equality in the workplace, singling women out as undependable.

And while some employers already quietly (and illegally) discriminate against female hires because of the potential for maternity leave, at least it is a specified period of time management can plan around. But how does it police abuse with a menses sick claim?

For Toyota Australia, for example, at any given time in the month 40 women theoretically could be on the special sick leave. And what about resentment on the part of their male counterparts?

Since the time of hunter-gatherers, women have had to deal with their reproductive health issues. It is nothing new. As early civilization developed, some societies shunned women as unclean during their monthly cycle. And some still do.

Do modern women, whether they are auto workers, secretaries, fire fighters, corporate executives, teachers or doctors, really want to be reduced to a workplace status that implies they cannot meet their obligations at certain times of the month?

Perhaps Toyota’s Australian workers should rethink their demand. Whatever would be gained under such a provision cannot compare with what would be lost.