Barbara Bush: I don't know how women can vote for Trump

Four days before the U.S. presidential candidates face a crucial primary in New Hampshire, Republican Donald Trump's rivals kept up their attacks on Friday with Jeb Bush and his mother scolding the front-runner over his use of profanity and treatment of women.

Polling following Monday's Iowa caucuses showed Trump retaining a double-digit lead in New Hampshire with U.S. Senator Marco Rubio rapidly rising into second place.

The billionaire's front-runner status was pierced by a second-place finish to U.S. Senator Ted Cruz in Iowa, where Rubio's strong third-place finish set him apart from the rest of the Republicans vying for the party's nomination for the Nov. 8 presidential election.

One of those rivals, former Florida Governor Jeb Bush, continued his attacks on both Rubio and Trump, with help from his mother, former first lady Barbara Bush. His brother, former President George W. Bush, also appeared in a new ad on Friday praising Jeb as having "a good heart and a strong backbone" and being able to unite the country.

In an interview on "CBS This Morning," Jeb and Barbara Bush attacked Trump as misogynistic and vulgar after he used a four-letter word in a recent campaign appearance.

"I don't think a president would have ever shouted profanities in a speech in front of thousands of people with kids in the crowd," Jeb Bush said. "He does it all the time."

His mother lambasted Trump for criticizing Fox News anchor Megyn Kelly during and after a Republican debate in August. Trump called Kelly names and made comments widely interpreted as referring to her menstrual cycle.

"I don't know how women can vote for someone who said what he said about Megyn Kelly," she said. "It's terrible. And we knew what he meant, too."

Jeb Bush also attacked Rubio as lacking experience, but his former protege has eclipsed him in the latest New Hampshire opinion polls.

Rubio got a bounce from his Iowa performance with a WMUR/CNN poll showing rising 7 points to 18 percent. Trump held steady at 29 percent, while Cruz gained 1 point for 13 percent. An NBC/Wall Street Journal/Marist survey showed Trump with 30 percent, Rubio at 17 percent and Cruz 15.

The Marist poll of 653 likely Republican voters was conducted Tuesday and Wednesday with an error margin of plus or minus 3.8 percentage points. The WMUR/CNN poll of 209 Republican respondents, conducted Tuesday through Thursday, had an error margin of 6.8 points.

(Reporting by Doina Chiacu; Editing by Bill Trott)