Fathers and sons

I'm developing this bad habit where I call fathers by their son's name. It happened most recently at church on Sunday, where I didn't recognise my error until the father burst out laughing and pointed it out to me.

There is one trick I use to deal with this problem. Let's say the father and son are called Joseph and Jesus, but I can't remember which name belongs to who. My brain then goes, "It's Joseph and Mary [wife's name], Joseph and Mary, Joseph and Mary, therefore the son's name is Jesus, and the father's name is Joseph!". My brain seems better at names of couples, rather than names of individuals.