Taking advantage of a new exception to the law that defines a child born within 300 days of a divorce as the former husband's, 20 women across the nation applied Monday to register their children under their current husbands' names.

The Justice Ministry rule that went into effect Monday allows birth registrations "as exceptions" for newborns if a medical certificate is presented to prove the pregnancy began after divorce.

A woman from Sumida Ward, Tokyo, applied to register her 4-month-old son under her current husband's name. The woman gave birth to the boy prematurely in late December on the 292nd day after her divorce.