one for all you fans of the old testament

Many happy years ago the Healy family lived in the bustling Dublin suburb of Tallaght.
The house in which they lived was a veritable chaos of rabbits, football games, chemistry sets, pop music, the Tomorrow People, Star Trek, Time Tunnel and Doctor Who.
One day a kind hearted optimistic young priest, newly arrived in the area, decided to pay a visit to this humble home.
The priest was fresh faced, ruddy cheeked, and somewhat innocent.
The Mammy invited him into the kitchen, put on the kettle, and motioned towards the chairs.
In one arm she held a baby. At her feet, a toddler who would later become famous as Ireland's greatest living poet, sat playing with his yellow plastic bricks. (Modesty prevents me from naming him.) Four other children beetled in and out of the room at various intervals demanding attention, intervention or subvention as the mood struck them.
The good hearted priest looked around wildly for some conversational sally that might establish common ground with the busy mother before him.
His eyes alighted on a canary, sitting in a cage at the window, singing sweetly of the joys of life.
"What a lovely canary!" exclaimed the Padre. "What do you call him?
The Mammy did not turn a hair.
"We call him Onan," she shot back. "Because he's always spilling his seed."