Reduced penetrance and variable expressivity are factors that influence the effects of particular genetic changes. These factors usually affect disorders that have an autosomal dominant pattern of inheritance, although they are occasionally seen in disorders with an autosomal recessive inheritance pattern.enetrance refers to the proportion of people with a particular genetic change (such as a mutation in a specific gene) who exhibit signs and symptoms of a genetic disorder. If some people with the mutation do not develop features of the disorder, the condition is said to have reduced (or incomplete) penetrance.
Although men have more muscle mass than women, both sexes reach their physical peak as young adults or anywhere from their late 20's to early 30's, according to âHuman Development: A Life-Span Viewâ by Robert Kail and John Cavanaugh.
As men age, their testosterone levels tend to decrease. According to the Mayo Clinic, most menâs testosterone levels peak in their 20s. After age 30 or 40, those levels tend to decline by about 1 percent per year. By age 70, your testosterone level might reach 50 percent of your peak level. This hormonal shift can cause physical, emotional, and cognitive changes.