Why do my young children have hardly any moles? Is it inevitable they'll get more as they age?

To misquote Shakespeare, some people are born with 'moles' and some have 'moleness' thrust upon them. Moles (pigmented naevi) are small areas of skin in which deposits of pigment (melanin) make them darker than the skin around them. In raised moles, the outer layer doesn't 'shed' like the surrounding skin, so they are 'lumpy'. A few babies have them when they are born, but for most they appear in the first few years. Why this should be isn't clear. It may be to do with the skin cells becoming more mature. Many have a crop of moles, and some have several hundred. Don't worry, because there's nothing we can do to stop children developing them.

Is it true that hypochondriacs actually get less ill than the rest of us? If so, why?

No, it isn't. Hypochondriacs are as prone to every real illness as non-hypochondriacs. In fact, hypochondria is itself a real illness, involving anxiety and often underlying depression. It isn't confined to adults: the worst cases are often in teenagers. Nor is it more common in women - that's another myth. Men can be just as anxious about their health as women, but they don't necessarily show it so obviously. We try to treat hypochondriacs with cognitive behaviour therapy, but in doing so we still check that the latest batch of symptoms aren't the sign of a physical disease. Disaster did eventually come to the boy who cried wolf.

· Do you have a question for Dr Smith? Email doctordoctor@theguardian.com