CAMBRIDGE, Mass. (AP) _ As Harvard celebrates its 350th birthday, Radcliffe has been absent from the hoopla. The official word is that all is well at the sister institution.

''We've had our days of sibling rivalry,'' said Margaret Touborg, executive assistant to Radcliffe President Mattina Souretis Horner. ''We are the younger sister. But we're here to stay and we're feeling good about Radcliffe's mission to give women a Harvard education.''

Radcliffe, established in 1879, is an independent college with its own board of trustees, administration, property and endowment of $65 million, one- fifth of Harvard's.

While women are admitted to Radcliffe, they are enrolled in both schools and receive diplomas signed by both schools' presidents.

Radcliffe was founded to give women access to a Harvard education, though they originally were barred from the libraries, classrooms and dining halls, and Harvard balked at absorbing Radcliffe.

''I have no prejudice in the matter of education of women and am quite willing to see Yale or Columbia take any risks they like, but I feel bound to protect Harvard College from what seems to me a risky experiment,'' wrote Treasurer Edward W. Hooper in 1893.

After World War II, women were allowed to join men in Harvard classes.

In 1977, the presidents of the two schools signed an agreement keeping Radcliffe a women's college, but recognizing Harvard as coeducational. About 2,700 women are enrolled this year.

Officials say the male-to-female ratio has improved in the past 15 years from 4 to 1 to 1.4 to 1.

''Harvard should have done more,'' said Margaret Rossiter, class of '66 and a historian at Cornell University. ''But Radcliffe didn't hassle Harvard. Radcliffe didn't bother Harvard. Radcliffe was grateful just to be there.''

She pointed out that women account for less than 7 percent of the 364 tenured faculty members.

''I wouldn't say Harvard has been at the vanguard of feminist institutions, but it's better than it would have been without Radcliffe,'' said Ms. Rossiter's former college roommate, Radcliffe trustee Rosalinda Reynolds Ratajczak.

''I think Radcliffe is a feminist institution but not an activist institution. I think we might get more done that way.''