Dangers of Thumbsucking

In a discussion of the habit of sucking one's thumb {The Cutting Edge, Dec. 11}, the conclusion that "thumbsucking in children under 5 is harmless and should be ignored by parents" should be rebutted. Research has shown that thumbsucking will cause improper swallowing patterns. The misalignment of teeth and jaws can be attributed, in part, to the tongue positions these children form while swallowing. Sucking one's thumb causes the tongue to affect the way the roof of the mouth develops, so that orthodontic corrections must be made at an early age. Steven A. LeBeau, DDS McLean

Teenage Girls Face High AIDS Risk

Your recent story {AIDS, Dec. 11} on women and AIDS raised many alarming points. Let me add another one: The HIV infection rate for teenage girls is consistently higher than the rate for boys. Overall, while male AIDS cases outnumber those among females 9 to 1, these statistics are turned on their head for teens. This is not a statistical blip. Rather, it is a well-documented finding -- from study after study of teenage military recruits, of Baltimore adolescents and, last but not least, a recent study of teens right here in the District. In fact, results of the soon-to-be-published D.C. study are especially troubling -- the HIV infection rate was 4.7 per 1,000 for girls, almost three times the 1.7 per 1,000 for boys.

There is evidence that the high, and still rising, rate of other sexually transmitted diseases, such as genital warts, among teenage girls dramatically increases their risk of infection with HIV. This means that teenage girls need to realize that they can contract HIV infection today and develop AIDS in their twenties. It means that school and community programs need to help girls -- and boys -- understand that they can contract and transmit AIDS during heterosexual intercourse. And it means that researchers need to wake up and take a serious look at HIV infection in females, especially those who are poor or minorities and thus at greatest risk. Margaret C. Dunkle Washington

Sexual Abuse and Multiple Personalities

No discussion of the devastating consequences of childhood sexual abuse {Focus, Dec. 4} is complete without acknowledgment that abused children who have the ability to dissociate, or go into a trance, are at risk for multiple personality disorder. This disorder represents a major disturbance of memory and identity and, as such, is potentially disruptive in all areas of functioning. It is not unusual for such a patient to have more than a dozen personalities.

Multiple personality disorder is far more common than it was once thought to be. Dissociation should be routinely tested for whenever there is a suspected history of early abuse and/or apparent memory disturbance. With appropriate treatment, the prognosis for this disorder appears to be better than is the case with other serious forms of psychopathology. Sarah Krakauer Williamsburg, Va.

Being Lefthanded

As a 57-year-old leftie, I really enjoyed the article on lefties' lament {Behavior, Dec. 4}. I feel that with advanced technology, being left-handed is more difficult. Many devices are so refined now that it is very difficult for us to use ordinary things, such as scissors, knives, electric can openers, garden tools. As a former elementary schoolteacher, I would like to encourage current teachers to spend a little more time with young lefties -- they see the world differently from the way the majority does. Jean P. Thompson Silver Spring Letters intended for publication must be signed and include the writer's home address and home and business telephone numbers. Letters may be edited. Although we are unable to acknowledge all letters, we appreciate the time and value the viewpoints of those who write. Send letters to Health Section, The Washington Post, 1150 15th St. NW, Washington, D.C. 20071.