At every stage of my career I have had interesting and cordial colleagues, some of whom are close friends.

As I look back on the last few decades of my life, I am struck by the good fortune that came my way.

So I applied to medical school and received a scholarship at Washington University in St. Louis. Washington University turned out to be a lucky choice. The faculty was scholarly and dedicated and accessible to students.

My education began in the public schools of Wilmington. During most of these years, from about age 10, I also worked at some job or other after school, on weekends, and in the summer months.

The glimpses of human strength and frailty that a physician sees are with me still.

My parents came to the United States in the early years of this century as part of a wave of Russian Jewish immigrants seeking freedom and opportunity in the New World.

First of all, many human diseases are influenced by, if not caused by mutations in genes.