“I don’t know that there’s any race in the history of presidential polling in Iowa that shows this kind of division,” said J. Ann Selzer, president of Selzer & Co., the firm that conducted the poll.

Trump leads by 21 percentage points with men, 57% to 36% over Biden. And Biden leads by 20 percentage points with women, 57% to 37% over Trump…

CNN exit polling of Iowa voters in the 2016 election showed Trump carried men by 28 percentage points, 61% to 33%. Democrat Hillary Clinton carried women, but by a smaller margin than Biden is now — just 7 percentage points, or 51% to 44%.

That migration of women over to Biden is a major factor driving the current race dynamics, Selzer said.