Q: Why do some people have a full head of hair into their seventies or eighties and others start to go bald in their late teens or early twenties? — E.Z., Darien, CT
A: The difference is genetic with the inheritance coming from either side of the family.
Although a person will have the genes his/her whole life, a gene’s expression (also called phenotype) can be quite variable. The factors that cause this variability are still unknown.
Read more about the Genetics of Hair Loss
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