Half of U.S. women say they have a “very unfavorable” view of the front-runner for the Republican presidential nomination, according to Reuters/Ipsos polling, up from the 40% who felt that way in October. The survey was taken from March 1-15, and included 5,400 respondents.

The rise in anti-Trump sentiment among women could pose a problem for the New York billionaire in his quest for the White House. Women form just over half of the U.S. population, and they have turned out at higher rates than men in every election since 1996, according to the U.S. Census Bureau.

“If the presidential election were tomorrow, women would be a big problem for Trump,” Republican strategist David Carney said. “But he has time to fix it.”

A Trump campaign official did not immediately respond to a request for comment, but Trump has said that he has had good relationships with women in his business career and is well-liked by women voters.

Several women who oppose Trump, interviewed by Reuters this week, said their disapproval was based on a range of factors from his disparaging comments about women he dislikes—such as Fox News host Megyn Kelly—to his hard-line views on immigration and his ribald exchanges with rivals.

“I think Trump is very scary,” said Mariah Dobias, a 25-year-old cook who was voting in Ohio’s primary on Tuesday. “He says he is going to make America great, but he doesn’t say how he is going to do it besides alienating whole groups of people.”

Carolyn Hostetler, a conservative from Tennessee, told Reuters she disliked “the way he has belittled women.”

Some of Trump’s female supporters, meanwhile, said they liked his straight talk, and believe he could strengthen America’s position on the world stage.

“He’s a little unpredictable, as we’ve seen,” said Kathleen Douglas, a 65-year-old college professor from Winter Park, Fla. who supports Trump. “He’s going to put other world leaders on edge.”

Trump does not have a similar image problem with men. The Reuters/Ipsos polling results showed that just 36% of men said they have a “very unfavorable” opinion of Trump, a level that has held steady in recent months.

Republican women are also much more likely to approve of Trump, according to Reuters/Ipsos polling. Among women who identify as Republican, he has been holding around 60% favorability since the start of the year.

Trump’s relative appeal among men versus women was evident in the most recent round of nominating contests on Tuesday, when Trump extended a broad lead over rivals.

In Florida, exit polls conducted by Edison Research showed that Trump’s support among Republican women voters was 40%, versus 52% among males. In Ohio, where Trump came in second to the state’s governor, John Kasich, 33% of women voters backed Trump, compared with 40% of men.

If the GOP frontrunner were to run against Democratic hopeful Hillary Clinton in the general election, likely women voters would support Clinton over Trump by nearly 14 percentage points, according to the March polling data. Among men, Clinton would win by about 5 percentage points.

At a precinct in Florida’s Winter Park, Darlene Monzadeh, a 52-year-old stay-at-home mom who had been a supporter of Jeb Bush, said Trump lost her vote during a debate when he exchanged potshots with his rivals.

“It changed my opinion. When they catfight all the time and act like little boys, pointing fingers, raising voices,” she said, adding she now supports Kasich.

Trump has been accused by critics of misogyny since he launched his campaign. He complained last year that Fox News host Megyn Kelly had asked him tough questions in a debate and referred to “blood coming out of her wherever.” He more recently sent a Twitter post suggesting she was a “bimbo.”

He has called television personality Rosie O’Donnell a “fat pig” and made fun of former presidential rival and ex-HP chief executive Carly Fiorina’s face, saying, “Would anyone vote for that?”

An anti-Trump attack ad launched by the Our Principles Super PAC this week featured women repeating words that Trump has used to describe women, including “fat pig” and “dog.”

Several of his female supporters defended Trump against the ad on social media.