Many aspects of human sexuality are very puzzling.
Take celibacy – this can be a choice in life, or a condition imposed by environmental factors:
Whilst attending a Marriage Encounter Weekend, Bill and Mary listened to the instructor declare “It is essential that husbands and wives know the things that are important to each other.”
He addressed the men, “Can you each name and describe your wife’s favourite flower?”
Bill leaned over, touched Mary’s arm gently and whispered, “Self-raising, isn’t it?”
…and thus began Bill’s life of celibacy.