Janet is 36 years old. She's doing well in her career as a nurse; she has lots of friends, and she's happy. She's also in no particular hurry to get married.

Her mother doesn't quite understand that. In her day, women just didn't live 36 years and not find a husband. She needs a husband, doesn't she?Or does she?

Theirs is a mother-daughter conflict that has become common as more women choose not to marry.

Marriage rates for educated young women in the United States are falling, a study by Yale and Harvard universities found. It also suggested that women like Janet might forgo marriage entirely rather than just postpone it.

Writer Patricia Curtis asked one of the researchers in the study, Patricia Craig, to take the project one step further and survey successful single women - and their mothers.

The resulting study is the basis of a new book by Patricia Curtis, "Why Isn't My Daughter Married?"

The survey showed that many women in their 20s and 30s today have fundamentally different perceptions of marriage than their mothers have, Curtis said in an interview.

"I'm perfectly happy with my life the way it is," says Janet, a resident of Evansville, Ind., who discussed the conflict on the condition that last names not be used. "I have a good career, lots of friends and am involved in community and church activities. I don't feel I need to be married."

Her mother says she wants her daughter to be happy and argues that women today can easily combine career and family. She wants her daughter to marry.

It was a familiar scenario, when laid out for Curtis.

"We have a lot of women like Janet who aren't all that desperate to be married," Curtis says. And those who are considering marriage want husbands for different reasons than their mothers did, she adds.

"Women today don't believe they need a husband for financial reasons. They want someone who's intelligent and who would be willing to help with the housework. They want husbands who will offer companionship, commitment and emotional support."

Their mothers were thinking more in terms of being protected and supported financially as well as emotionally, Curtis says. The mothers perceive the perfect husband as being older, better educated and able to be a good provider.

SOME WOMEN TODAY, HOWEVER, want an intelligent man, but he doesn't necessarily have to be as well educated or earn as much money as they do.

"Women today get emotional support from friendships, they're committed to their jobs and they are involved in interesting activities," Curtis says. "They're not just sitting home by the telephone, waiting for a man to call."

Daughters often are finding satisfying, committed relationships outside of marriage, including live-in boyfriends or other single relationships.

Daughters surveyed by Curtis are "very much aware of the high divorce rate." Many of their peers have unhappy marriages, and for that reason, the daughters can be "quite cautious" about marriage.

"I have a theory, but no evidence, that by being more selective, these women's actions might ultimately lower the divorce rate. If they finally do marry, they're not marrying for the wrong reasons."

But single women still feel the pressures from society - and from their mothers - to marry. It's how they deal with it that's important, Curtis says.

Janis Lotfalian, a family counselor, points out a woman's "biological clock" is ticking during her 30s, forcing a decision about having children.

"That's the time when women have to evaluate their lives and their goals - to decide whether marriage fits in with their lives."

But the biggest pressure facing the daughters is not self-imposed, but from relatives and society in general, Curtis says.

Pat MacCorquodale, associate professor of sociology at the University of Arizona, says single women cope with such pressure in three ways.

- Some become defensive and claim they're single because that's the lifestyle they want.

- Others go on with their lives and enjoy careers, friends and activities. They hope to marry but are satisfied with their lives even if they don't.

- Some become desperate and try any means to find a mate.

Many have become overly concerned about numbers - the ones showing considerably more women than men are available for marriage, MacCorquodale says. "The ratio of women to men isn't as important as making time and finding ways to introduce new people."

Still, parents always have hopes for their children, MacCorquodale believes. "That's why we put time and energy into children. And that won't ever change."