DEAR ABBY: I am a 36-year-old woman with a wonderful husband and a terrific 4-year-old son. I also have a very immature, unmarried 21-year-old stepdaughter, "Dolly," who is expecting a baby any minute. The baby's father disappeared when Dolly announced her pregnancy. She wants to keep the baby, and I have been getting a lot of pressure from my husband's family who think the logical place for Dolly and her baby is with her father and me.

Abby, I don't want Dolly and her baby moving in with us because Dolly has always been lazy and irresponsible and I'd have to take care of the baby. Also, I had planned on returning to college in the fall when our son will be in school full time.I feel strongly that since Dolly decided to have sex, decided not to have an abortion and decided to keep her baby, the baby is her responsibility - not mine. Need I tell you how unpopular my decision has made me with my husband's family? He does not blame me, but his mother and sisters think I am selfish, cruel and unreasonable - although they did not offer to take her in. How do you vote, Abby? Sign me . . . THE WICKED STEPMOTHER

DEAR "WICKED": I'm voting with you. There is no reason why you should postpone going back to school because your husband's daughter decided to keep her baby.

Dolly is old enough to accept responsibility for her actions and decision. And she's lucky to have a grandmother and aunts who are so concerned about her welfare, because if she's as immature as you say she is, she'll need all of their assistance in learning to shoulder the emotional and financial responsibilities that go along with single parenthood.

DEAR ABBY: Your answer to "Overtaxed," the couple who was trying to find a clergyperson to quietly bless their spiritual bond - while the IRS would consider them to be still in a "singles" tax bracket - was both inaccurate and unkind. Wanting to have the church sacrament of matrimony without the IRS's unspeakable tax penalty for married persons is not "crooked," Abby. It is reasonable and moral. It is also easily achieved in Texas.

As a Texas lawyer and church member, I sympathize with your reader. "Holy matrimony" and "legal marriage" are not the same thing.

There are thousands of Christian clergymen in most denominations who consider their Christian function more important than their governmental one, and the two are unrelated. They will not require a state marriage license, nor will they report the ceremony to the state, since they are performing a sacrament involving only the couple, God and the church.

If the couple desires a legal marriage, after living together and establishing themselves as a married couple, in time, they are indeed legally married by common law. In Texas, such a marriage need not be recorded, yet both parties and their children enjoy all the legal rights of a formal marriage before a judge. (They should, of course, not lie on their tax returns.)

If either of these arrangements hurts the feelings of the folks at the IRS, too bad. They weren't invited to the wedding and wouldn't have sent a gift if they had been invited. The government loses nothing but its chance to encourage and reward "living in sin."

In memory of Romeo and Juliet's "crooked tax-evasion" . . . A SECULAR FRIAR LAURENCE

What teenagers need to know about sex, drugs, AIDS, and getting along with their peers and parents is now in Abby's updated, expanded booklet, "What Every Teen Should Know." To order, send a long, business-size, self-addressed envelope, plus check or money order for $3.95 ($4.50 in Canada), to: Dear Abby, Teen Booklet, P.O. Box 447, Mount Morris, IL 61054. (Postage is included.)