Two of them were nuns, although one identified herself as a retired school teacher. Two were mothers, one of them three months away from delivering her fourth child. They were all Catholic, all anti-abortion, and they were testifying about teen-age pregnancy, sex education and natural family planning.

They came as emissaries from the pro-life movement to testify last week before the House select committee on population and they were there to make a case for chastity, a case for saying no, a case against the pill and intrauterine birth control devices and in the end they found common ground with women on the radical, feminist left.

"It's okay to say no," said Regis Walling, a nun who identified herself as a retired government teacher who is now directing a statewide group that helps pregnant wome in Michigan.

"I suggest that any sex education program which defines youth as 'potential contraceptors' and 'statistics' has lost sight of the person to be reached. There is widespread acceptance of the idea that 'everybody's doing it," she said.

"This, too, degrades youth. Planned Parenthood gives us the statistic that 35 percent of the teen-age girls have experienced intercourse by the time they are 19. This leaves 65 percent who have not had even one encounter - a 2-to-1 majority," she said.

Then she began cataloguing what she said are the evils of teen-age sex (high venereal disease rates, alienation from parents and family, loss of self-esteem) and the bad side effects of the pill, particularly on young women.

"From the onset of menarch (menstruation) it takes three to five years for the endocrine system to complete its development and attain a balance. Potent estrogens interfere with this normal maturation process," she said.

Her attack on the pill and her defense of teen-agers' virginity provoked the first of several profeminist outbursts by Rep. James Scheuer, a liberal Democrat from New York.

"The whole women's movement is that they can make decisions and have options and saying no is one of them," he said. He said he objected to "the contraceptive mentality," and added that earlier hearings had produced a "great deal of testimony from women's groups that male decision-makers were producing contraceptives with harmful chemicals."

He had touched the problem. Although the witnesses spoke of teenage pregnancy, the hearings really had to do with family planning and the growing belief among women that birth control devices that are safe against pregnancy aren't safe to use, and that the safe, natural methods of birth control are not safe against pregnancy. In other words, we haven't come such a long way.

The pill also was assailed at the hearings by Dr. John Marshall, one of the Health, Education and Welfare Department's top community health officials."The pill is not appropriate for every woman," Marshall said. "I certainly wouldn't want my wife to take the pill. Why mess up her whole endocrine system just for that purpose?"

The women testified in favor of natural family planning, a term used to describe birth control that does not depend on the women ingesting chemicals or using preventive devices such as the IUD National family planning, the women witnesses said, requires the woman to monitor her own body in one of several ways to find out when she can become pregnant. During her fertile period, they suggested, she should abstain.

"Natural family planning is information about their bodies every woman should have," Scheuer said. "She can know when the fertile period is and choose whether or not to abstain. I think that's basic information every young woman would want to have about her own body. I would think that would be SOP - standard operating procedure."

Later, several witnesses, including Jeannette Reinecker, the pregnant mother of three, a veteran of the pro-life movement, were standing in the hallway. Dr. Rhonda Einhorn, a researcher on the committee staff, was recalling earlier hearings in which women from the National Women's Health Network - "a very radical women's group" - testified. "They said they don't want the IUD, the pills. They're women. They know what these things do.'"

Reinecker, 29, a primary school teacher who has spent most of her free time in recent months in pro-life lobbying before the Maryland state legislature, seemed to agree.

She spoke of the effectiveness of natural family planning, of advances being made in the methods, and later she testified in detail, citing statistics from planned parenthood making it as effective as the pill and vasectomies, if the woman monitors her body carefully. "We've come a long way since the calendar rhythm method," Reinecker said.

"There is actually a lot of agreement between women on the right and women on the left," Rhonda Einhorn said at the end of the session. "The president of the right-to-lifers is against a lot of methods. The pill is unhealthy and the IUD is unhealthy. We asked her what about the foam, condom and diaphram. She said 'I would approve of those.' When (a representative) of the Women's Health Network came she said the same thing. There is actually a lot of agreement if they'd get together and talk, and not let the issue of abortion get in the way."