The administration of Donald Trump — who had a child out of wedlock after cheating on his first wife, and is in a legal battle with a porn star who says she had sex with him not long after his third wife gave birth — is promoting abstinence with a zeal perhaps never before seen from the federal government.

Mr. Trump’s Department of Health and Human Services is quietly advancing an anti-science, ideological agenda. The department last year prematurely ended grants to some teen pregnancy prevention programs, claiming weak evidence of success. More recently, it set new funding rules that favor an abstinence-only approach. In reality, programs that use creative ways to educate teenagers about contraception are one reason teen pregnancy in the United States has plummeted in recent years.

The administration is promoting a “just say no” approach to adults as well as to teenagers. It’s poised to shift Title X family planning dollars — funds largely intended to help poor adult women around the United States get birth control — toward programs that advocate abstinence outside of marriage, as well as unreliable forms of birth control like the rhythm method (though the health agency might have to reverse course if either of the lawsuits filed against it last week by Planned Parenthood and other women’s health advocates are successful).