Q I've heard about wallboard from China that is causing problems in new houses. How do I know if I might have it?

A In recent years, basically from 2004 to 2008, some drywall in the United States (mostly in the South) was contaminated with sulfur compounds, causing it to emit sulfur dioxide, often, noticeably so. Occupants could detect an off odor, but not always.

In either case, the gas reacted with electronics, copper and other metals in a house. Electronics might malfunction, metal items such as copper would discolor. In some instances, occupants complained of irritated eyes, headaches and nosebleeds.

To determine the origin of your wallboard, look at the back of an unfinished wall, say, in the basement. If the dry wall is stamped "Made in China," you need to be concerned. Otherwise, no.

Moms and baldness

Q Is it true that if a man goes bald, it's because of his mother?

A. Sooner or later, everything seems to be the mother's fault. But not this time, at least not all the time.

Baldness is a sex-limited trait. That means either sex can inherit the gene for baldness and pass it on to any child. But a male who receives the gene will show the trait, while a female will not.

Females must inherit genes from both parents in order to show the trait.

Information from the University of Minnesota

Norwex cloths

Q I recently bought products made by Norwex, a party plan similar to Tupperware. I paid $35 for a cleaning cloth and a polishing cloth, which work wonderfully on windows, etc., with no streaking. They supposedly have silver in them. Now, I have discovered similar cloths at my local Dollar Store. They look the same as the Norwex cloths, but cost $1. I've used them and can see no difference. Have I been had?

A It depends on what you expect of the cleaning cloths.

Microfiber cleaning cloths are widely available. They have specially constructed fibers that grab and hold tiny particles of dirt and dust as you wipe. They are great for cleaning and dusting.

The microfiber cleaning cloths from the Norwegian company Norwex, however, are infused with silver. In that respect, they aren't like other microfiber cloths. Silver is a well-known and effective disinfectant, but the Norwex cloths don't work as you might suspect. Rather than kill bacteria on contact, they remove them from the surface.

According to Norwex, the cloths pick up 99 percent of all bacteria on a surface as you wipe. When you rinse or wash the cloths, much of the bacteria is washed away. The company claims it removes 99 percent of bacteria on the surface. What remains in the cloths is destroyed by the silver. This prevents bacterial growth on the cloths.

You'll have to decide if the disinfection property is worth the price. At the least, review how you use the cloths. The expensive cloths might be best used on germier surfaces, while others would work for windows, for example.

Send your questions to Fixit in care of the Star Tribune, 425 Portland Av. S., Minneapolis, MN 55488, or call 612-673-7032, or e-mail fixit@startribune.com.