An 80 year old man goes to the doctors and is told to take a jar home and come back with a sperm sample.
He returns 2 days later with an empty jar.
Doctor asks him why, the man replies " I tried with my right hand tried with my left hand the wife tried using both hands then she tried with her mouth, she tried with her teeth in then with her teeth out, we even had Ethel from next door have a go but we still couldn't get the lid off"