Many aspects of human sexuality are very puzzling, take celibacy.
This can be a choice in life, or a condition imposed by environmental factors.

While attending a Marriage Encounter Weekend, Fred and Julie 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?'

Fred leaned over, touched Julie's arm gently and whispered,

'Self-raising, isn't it?'

Thus began Fred's life of celibacy.