Koizumi, son of charismatic former prime minister Junichiro Koizumi and seen as a future leader himself, said he would take about two weeks of leave over three months following the birth of his first child this month.

Japanese Prime Minister Shinzo Abe has been trying to encourage more men to take paternity leave, and for businesses to allow a better work-life balance, as part of his “Womenomics” program of bolstering women’s employment.

But change has been slow. Some other lawmakers initially criticized Koizumi’s interest in taking parental leave, saying he should prioritize his duty to the public.

Koizumi said he decided to set an example for other men, but had struggled as he weighed his responsibilities as a minister against those of a father.

“Data shows that 80 percent of men, upon joining the work force, say they’d like to take paternity leave, but only 6 percent of them actually go through with it,” he said in a speech, which was also posted on his website.

“I now understand the reason for this gap... So many other men are facing this same conflict, of wanting to take leave but being unable to do so.”

Japan’s parental leave policies are among the world’s most generous, providing men and women with partially paid leave of up to a year, or longer if there is no public child care. Policies are even more accommodating for government workers.

But just 6 percent of eligible fathers take child care leave, and most of them for less than a week, according to government data.

That is double the 3 percent rate of a few years ago, but far short of the 13 percent target set by the government for 2020.

“At a time when they’re calling for work-life balance, his taking childcare leave is a way of raising awareness. I think he can be given credit for that,” said Tomoaki Iwai, a political science professor at Nihon University.

The telegenic Koizumi, popularly referred to as Shinjiro to distinguish him from his father, was appointed to the high-profile post in September. This was shortly after grabbing headlines with news that he was marrying Christel Takigawa, a French-Japanese television personality.

He has said Japan should eventually get rid of nuclear reactors, but he has also called for a low-carbon future, although he has yet to propose specific policies on how Japan should wean itself from its dependency on coal.

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