"It was the wrong thing to say," Obama told WCMH-TV in Columbus, Ohio. Criticism of candidates' spouses should be out of bounds, he added.
Polls show women lean heavily Democratic and favor Obama by a wide margin in battleground states. Romney must win about 40 percent of the women's vote to have a shot at denying Obama a second term in office. His campaign has focused on winning over married women and mothers, who tend to be more conservative, and thus diminishing Obama's base of support.
Romney did not comment on the furor, but Ann Romney did, saying raising five sons is hard work and that while she never has worried about finances, she has faced the ordeals of cancer and multiple sclerosis. Further, she said, Mitt Romney considers her job, raising the children, as more important than his, which generated the family's net worth of more than $200 million.
The spat crackled across the twittersphere and cable television Thursday, reflecting the import of female voters to both campaigns and the volatility that remains over women's issues in political discourse.
Weighing into the debate: Vice President Joe Biden; female surrogates for Romney who said they were outraged by Hilary Rosen's words; first lady Michelle Obama; and the president's top campaign strategists. All defended mothers and the inevitable choices all of them must make.
Then Obama elevated the discussion, reflecting an intent to leave nothing to chance when it comes to one of his most loyal constituencies. For the first time this year, he and his Democratic allies were on the defensive on women's issues.
Romney's team pounced on Rosen's remarks, casting them as indicative of a pattern of intolerance inside the president's political organization.
For her part, Rosen at first buckled down and refused to apologize. But after Mrs. Obama tweeted her support for all mothers, Rosen said she was sorry to have offended Mrs. Romney or any other women.
A parent herself, Rosen said her point, stated poorly, was that Ann Romney had the luxury of choosing whether to work outside the home, whereas most American women must work to pay the bills.