As well as the ever-present danger of cars speeding around narrow roads and the hassle of lugging strollers up and down staircases, parents in Japan with babies in tow have long had to struggle with public restrooms the size of telephone booths.

Every parent knows that answering nature's call with a wiggly kid in your arms is like endurance training.

On weekdays, when dad wasn't around to help, many new mothers once rationed their liquid intake to avoid the need to go; others just stayed home. For men, meanwhile, the problem was all the more reason not to take baby out by themselves.

So, in 1990, Tokyo-based juvenile-products maker Combi introduced child seats with restrainer bars, called Bebii Kiipu (official English name: Baby Rests), that fit snugly in toilet stalls. With pink highlights, they were originally targeted at women, and department stores and supermarkets eager to lure female customers installed lots of them in their powder rooms.

Then a few years later a funny thing happened. Those pink chairs started appearing in men's toilets, too -- not only at department stores but also at do-it-yourself home centers, train stations, airports, family restaurants and hospitals.

The message to dad was subtle but clear.

"This was a part of the growing worldwide belief that parenting is not just for mothers, but fathers too," said Yutaka Kondo, chief of planning at CombiWith, the Combi subsidiary in charge of developing Baby Rest.

Combi doesn't publicize Baby Rest unit sales, but Kondo did estimate that about a fifth of its Baby Rests end up in men's stalls. And shipments have swelled by about 20 percent every year yearly -- a reflection, he says, of the modern thinking. In response to the new demand, Baby Rests now come in gender-neutral tones of white.

Baby Rests ain't cheap, with units priced as high as Y158,000. But smart retailers are stocking up.

"If our facilities are perceived as inconvenient, customers will naturally go somewhere else," observed Masaki Nishino, spokesman for Seibu department store's Higashi Totsuka branch in Kanagawa Prefecture, where all restroom stalls -- men's and women's -- are equipped with Baby Rests.

Likewise, restrooms there for both sexes are equipped with drop-down platforms for changing babies' diapers and feature stalls with extra floor space for strollers.

Meanwhile, giant multipurpose restrooms nearby can fit entire families, so that dad can change a newborn's diapers on the platform while mom helps her preschooler use the adjacent mini-toilet bowl.

Alas, as might be expected, not all dads are thrilled.

After all, all this nixes any justification for leaving offspring with mom while they go on solo weekend fishing excursions.

"There are no excuses any more," said one father. "Wives can now insist that we take the kid along."

But, either way, much work remains to be done before Japan can call itself a parent-friendly country in the manner of, say, Sweden, which has elevators galore and stairwell tracks for baby carriages.

Japan's government, to be fair, has acknowledged the problem, intoning in a guideline last year that whenever possible spacious restrooms must be made available to "create a barrier-free society for families."

But a statute promoting those lofty goals going into effect in April, called the Law for Measures to Support the Development of the Next Generation, only vaguely requires local governments to draw up plans without mandating specifics.

Those specifics shouldn't really be all that hard to figure out.

They could start, for example, by getting those ubiquitous midnight construction crews to construct some sidewalks.

Or deploy buses with space for carriages, like Sweden has.

Or put more elevators in stations.

But ask any mom, and she'll surely agree: Baby Rests are a good start.