Wrong Religion

Wee Sammy comes running into the kitchen.
'Mammy, Mammy, he says, 'I want to get married to Jimmy next door.'
'Don't be silly,' says his mother. 'It's impossible.'
'But why. Mammy? I love him.'
'Yer daddy will tell you when he gets home.'
So Sammy's daddy arrives home, and wee Sammy runs up to him.
'Daddy, Daddy, I want to marry wee Jimmy next door.'
'I know,' says his daddy. 'Your mother told me.'
'Well, can I?' asks wee Sammy.
'Certainly not, says his daddy. 'It would never work.'
'Why not. Daddy?'
'Because he's a Catholic.'