Former Yale provost and current Massachusetts Institute of Technology President Susan Hockfield joined the presidents of Princeton and Stanford universities late last week in criticizing Harvard President Lawrence Summers for his recent claims that women are under-represented in scientific fields because of biological “innate differences.”

The joint press release from Hockfield, Princeton President Shirley Tilghman and Stanford President John Hennessy, all three of whom are scientists, also pressed for greater encouragement of women interested in mathematics, engineering and the natural sciences. The presidents released their statement last Thursday, and it was published in the Boston Globe Saturday.

“One of the most important and effective actions we can take is to ensure that women have teachers who believe in them and strong, positive mentors, male and female, at every stage of their educational journey — both to affirm and to develop their talents,” the release said.

According to National Science Foundation records, women are entering scientific fields in larger numbers in the long run. While only 16.9 percent of doctoral degrees in engineering were awarded to women in 2001, that number stood at 0.3 percent in 1966. The percentage of doctorates earned by women in the biological and agricultural sciences rose from 12 percent to 43.5 percent during the same period.

Hockfield and the other presidents pointed to these national trends as signs of progress but said much more needs to be done to keep scientific fields from being seen as anachronistic in America.

“The nation cannot afford to lose ground in these areas, which not only fuel the economy, but also play a key role in solving critical societal problems in human health and the environment,” the release said.

Yale Provost Andrew Hamilton, Hockfield’s successor, said he had not yet read the statement, but he said Yale has emphasized diversity in faculty recruitment, citing the tenure of two women in the astronomy and ecology and evolutionary biology departments and the appointment of two female professors within the physics department.

“We are committed to increasing the number of outstanding women scholars on the faculty in general, but particularly in the sciences,” Hamilton said. “We are making progress, but there is still much to be done.”

Harvard administrators have already moved to curb the criticism of Summers’ remarks. On Feb. 4, Summers created two new committees to recommend ways to recruit and support women. The committees are to finalize their recommendations by May 1 so that they can be implemented for the fall term.

Hockfield could not be reached for comment over the weekend.