What is it about sex that generates such profound emotion across all cultures and generates issues we literally have to deal with from cradle to grave?

Sex issues dominate our life, from discrimination, sexism in society, good or bad relationships and domestic violence, deviant behavior, crime, the adult industries, others thinking they can determine what’s right and wrong for others to do. I could go on forever. It’s three little letters, yet we will deal with it more than any other single issue in life. Why?