We are born sexual animals and we maintain levels of sexual interest throughout our lifetime. And it is continually changing. Sex is full of wonder and mystery - it is not something we can understand. We still do not know why some people have homosexual preference and others hetero. Hetero-sexuality is the predominant norm in our society, and yet we need to make room for the alternative sexual life styles that emerge.
Sex is only one aspect of our humanity.
That is, some combination of male and female genitalia are present. This shows us that there is both male and female within each of us, and we are all different. What is of primary importance is the holding, caring, nurturing, playful, creative dance of sensual expression. There is an infinite variety of sensual play - kissing, hugging, dancing, etc. Sexually transmitted diseases are indeed a problem in our world.