Young love.
 

A young lad had a promise off his girlfriend they would do it for the 1st time tonight. So being young and nervous he called in the chemist for advice and condoms. The chemist was very helpful with all the advice and sold the boy a pack of 10. Later that evening he was invited to the girls house for dinner with her parents. Sitting at the table he offers to say grace before they eat, the boy leans over to say grace, after 1 minute he his still saying grace, 10 mins later he still saying grace, after 20 mins his girlfriend leans over and says, i didn't know you were religious, the boy whispers, i didn't know your father was a chemist.