DR. WALLACE: You said that marijuana is a "gateway" drug that leads to cocaine, heroin, PCP and other hard drugs. I smoke pot occasionally, but I have no desire to try the hard drugs you mention. The only thing marijuana is a gateway to is a pleasant high. Please rethink your marijuana gateway theory. — Bob, Madison, Wis.

BOB: Marijuana is, indeed, a gateway drug that can lead to the use of hard drugs. This simply means most users of cocaine, heroin, PCP and other illicit drugs started their drug career by using marijuana. Of course, all marijuana users do not advance to hard drugs.

WHAT IS CAUSE OF DOWN'S SYNDROME?

DR. WALLACE: My brother and his wife recently had a baby who was born with Down's Syndrome. What causes Down's Syndrome and are Down's Syndrome children retarded? — Nameless, Willmar, Minn.

NAMELESS: Down's Syndrome is a genetic disorder that occurs approximately once in every 1,000 live births. It affects people of all ages, races and economic levels and is one of the most frequently occurring chromosomal abnormalities.

The condition is named after Dr. J. Langdon Down, an English physician who first described its characteristic features in 1866. However, the genetic basis for the condition was not discovered until 1959, when French doctor Jerome Lejeune discovered that it resulted from the presence of an extra chromosome.

Most people with Down's Syndrome have IQs that fall in the mild to moderate range of retardation. Children with Down's Syndrome are definitely educable. People with Down's Syndrome usually live at home with their families and are active participants in the educational, social and recreational activities of the community. They are usually integrated into the regular education system, and take part in sports, camping, music, acting, art and all other activities.

The great majority of those with Down's Syndrome are productive, law-abiding citizens.

I DON'T KNOW A POT SMOKER

DR. WALLACE: You said that one in five high school students smoke marijuana. I find this high percentage very hard to believe. Please tell me where you got this information. I'm 16 and don't know anyone who is a pot smoker. — Sarah, Salt Lake City, Utah.

SARAH: I wrote that about 20 percent of high school seniors had smoked marijuana at least once in the past 30 days. My source was the American Medical Association. Marijuana is the most popular illegal drug used by teens, according to the AMA. The good news is that the percentage of teens who use pot regularly (at least once a week) is on the decline.

Dr. Robert Wallace welcomes questions from readers. Although he is unable to reply to all of them individually, he will answer as many as possible in this column. E-mail him at [email protected]. To find out more about Dr. Robert Wallace and read features by other Creators Syndicate writers and cartoonists, visit the Creators Syndicate website at www.creators.com.