‘90s FAMILY : Teen Romances : What to do when your kid brings home a dubious friend or mate? Bite your tongue, experts say.

Who would ever believe that the teen-age daughter of a devoutly religious parent would bring home a boyfriend who affected a skinhead look?

Sherill Sedillo would. Her daughter did.

“The more we pushed her to give him up, the more she rebelled to be with him,” says Sedillo, of Capistrano Beach, an ethnic Jew who has converted to Christianity. “We did forbid the relationship, at times, but she would just sneak out. What could we have done, other than lock her in her room? What could you do?”

And so began another round in that balancing act between anxious parents and adolescents who are forging their first serious romantic relationships.

What parents do--or don’t do--when their kids stroll in with that unpalatable someone can set the tone for either stubborn rebellion or a brief infatuation, psychologists and parents say.

Nit-pick the kid about body piercings and purple hair and the teen alliance may grow stronger for the attack. The parent who resists hitting the panic button but watches, listens a lot and talks a little is less likely to be slammed out of their teen’s life, says Mary Collier, a licensed clinical social worker for the Family Service Assn. of Orange County.

Proceed as if you have “a huge piece of duct tape across your mouth,” Collier says. “Start listening, because all parents lecture and they just go on and on.”

Naturally parents don’t want to dismiss their hunches or concerns, Collier says. There are some basic and obvious warning signs of trouble, like extreme withdrawal from family, refusal to talk, truancy, secretiveness and sudden abandonment of all old friends.

But snap judgments made on the basis of appearances rather than behavior and actions can spark a battle. Hold that duct tape image long enough to hear the kid out after a few questions have been asked. Who is this kid? What does he or she like to do? How did you meet? When are you inviting them over?

The latter may embarrass teens. But Collier, who has raised four teen-agers to adulthood, suggests an age-old lure.

“It doesn’t hurt to have food around,” she says.

And space. Parents should say hello but keep small talk brief and find something to keep themselves busy and out of hovering range.

“Allow them to just hang out,” she says.

Anxious parents might also want to look within themselves for the roots of their worries. A child’s first steps into romance often coincide with the parents’ middle-age rumblings, says adolescent expert Laurence Steinberg of Temple University. Steinberg’s newest book, “Crossing Paths: How Your Child’s Adolescence Triggers Your Own Crisis” (Simon & Shuster, 1994) explores how adolescence affects parents who may be re-evaluating their lives and feeling pangs of regret or loss.

“These big steps in the child’s life are big steps in the parent’s life, too,” he says.

In his studies, Steinberg found that fathers were particularly reminded of their age and midlife sags and bulges when their sons started going out with girls.

“On some level fathers may be somewhat jealous of their sons’ freedom,” he says.

It doesn’t necessarily mean that they are ripe for affairs or truly want to be young again, but it can exacerbate whatever midlife drama may already be underway, he says.

“It is a reminder, a very powerful reminder of one’s lost youth. And I think it happens for mothers and daughters, too,” he says.

The coincidence of midlife and adolescence under one roof can be a collision, or an opportunity, Steinberg says. Parents who embraced the transition as one of life’s normal events, generally coped well and thrived. They didn’t anticipate extraordinary woes, so the woes didn’t materialize, he said.

They were the type of parents who set limits, rules and curfews and talked about behaviors, rather than people.

“If it is a serious situation, whether it be safety, drugs or crime, then I think you sit your child down and talk about specific behaviors. Don’t try to cast aspersions on the dating partner. But rather say, ‘We have rules around here about driving and drinking or curfews,’ or whatever. . . . You want your child to understand that it’s the behavior and not the person you’re objecting to,” Steinberg says.

Anytime the chance arises, parents can also talk in general about relationships, without endorsing or rejecting the sweetheart of the moment.

“Kids are still trying to figure out how to be in a relationship,” he says. “Take it as an opportunity to discuss relationships. What’s a good relationship? How do you tell if a relationship is getting bad? Kids are wondering about these things. Their parents may have some pretty good advice and some pretty good experience to draw on. Kids on the younger side of adolescence are usually interested in hearing about their parents’ experiences.”

And how. The Wilsons of San Juan Capistrano make dinner-table conversation and discussion a high priority, in part to gently feed their children their own life lessons and values. Joanne Wilson and her husband both were previously married and often share their own early mistakes in dating and marriage.

“Kids are always all ears to hear about your mistakes,” Wilson says. “I think, too, that they see that we were human. But they also don’t like us to get too preachy. We try to make our little statements quick and short.”

One mother of two daughters used a variation of that tack. Her younger daughter dated a boy she suspected was using drugs, although there was nothing she could prove.

“So we had a lot more conversations with our kids about life choices and how even hanging around someone can be dangerous, without trying to point a particular finger at this kid,” says Bonnie, who didn’t want her last name revealed.

About a year after the boy had been dropped by the girl, Bonnie’s daughter asked why her parents hadn’t forbidden the romance.

“I asked her what would she have done if I had said, ‘You can’t see him anymore, he’s a bad choice.’ She said she probably wouldn’t have listened. I said that’s what I thought, too. She said, ‘I’m going to have to remember all these things when I’m a mom.’ That was kind of neat,” Bonnie says. “Unfortunately, you’re just never sure you’re doing the right thing. We just hoped so.”

Sherill Sedillo thought she was doing the right thing, too. She and her husband were convinced the boy was wrong for her daughter. He was older. He hadn’t cut all the ties with his skinhead friends. And before it was over her daughter was a teen mother.

But even with the luxury of hindsight, Sedillo says she’s not sure there’s anything she could have done differently. It was scary. It was frustrating. But she discovered that a parent’s disapproval can be the surest cement for a teen relationship.

Just like Romeo and Juliet.

“I really feel that if you hold them too tightly, you just lose them altogether,” she says.