Q: I have 12-year-old identical-twin daughters. One is resentful toward her twin; she wishes desperately that she were a singleton and becomes frustrated when her sister wants to do the same activities.

I see them as individuals, but I will not deny one girl the opportunity to pursue an interest (like theater, in a school with just one drama club) so the other can experience the interest on her own.

I'm sure this is a phase she is going through, but this growing chip on the one daughter's shoulder is upsetting her sister and me. Any suggestions?

A: With puberty comes a process called individuation, where adolescents go out of their way to prove their individuality. It's likely your daughter is going overboard to assert her independence not only from Mom and Dad but also from her twin sister.

Affirm her individuality by saying, "You're an individual, a unique person. Although you've an identical-twin sister, you've a personality and style all your own."

In addition, call attention to incidences where she's proved this fact to be true. Let's say you're all going to the movies, and the twins disagree as to which movie to see. Seize this opportunity to point out their unique interests: "It's amazing that you two are so different — one wants to see a comedy, and the other wants to see an adventure show."

Or recall a situation where each demonstrated individual personalities, "Remember the time when you were little and we went to Grandmas to make cookies? You got right in and helped, and your sister sat on my lap, insisted on me reading her a story and showed no interest in making cookies at all."

Such stories will, in a subtle way, drive home the point that they do not have cookie-cutter personalities. Also, notice and talk about their different emotional responses to the same situation: "Here you are identical twins, and one of you felt happy at the soup kitchen helping to feed the homeless, and the other felt sad seeing all the homeless people."

With regard to drama club, it would be easier for one daughter to distinguish herself from her twin if the other were not involved. If one twin wanted to dress just like her sister, you could prevent that from happening. But you can't stop, as you've explained, one from pursuing an interest or talent.

Here are three approaches to take with the daughter who does not want her sister in the drama club:

• Affirm her wishes by saying, "I know you wish you were a singleton. You also wish your sister would not be in drama club with you. You wish she would have a hobby or interest completely different from yours." This statement communicates that you understand her point of view and respect it.

• Set the limit by saying, "While I understand your wish for autonomy, you'll always be a twin; that's the way you were born. Furthermore, I can't forbid your sister from joining drama club. She has as much right to join as you do."

You can go on to explain the genetics of identical twins by telling her that each of them has the same genetic makeup, therefore, each may have inherited a talent for drama. In time she'll come to this understanding, but for now she would like her sister to take up chess.

If she keeps bringing up the issue of drama club, don't engage in a debate. Just restate her wishes and repeat the limit you've set, matter-of-factly. In time she'll turn bored receiving the same response and end the discussion.

• Lastly, continue to point out in as many subtle ways as possible the uniqueness of these two girls. There's no need to deny their similarities, but notice differences too.

Jan Faull, a specialist in child development and behavior, answers questions of general interest in her column. You can e-mail her at janfaull@aol.com or write to: Jan Faull, c/o Families, The Seattle Times, P.O. Box 70, Seattle, WA 98111. More columns at www.seattletimes.com/columnists