Very old, but it's a twin joke - so thought we'd throw it in...

A woman has twins, and gives them up for adoption.
One of them goes to a family in Egypt and is named "Amal."
The other goes to a family in Spain; they name him "Juan."
Years later, Juan sends a picture of himself to his mom.
Upon receiving the picture, she tells her husband that she wishes she also had a picture of Amal.
Her husband responds,
"But they are twins-if you've seen Juan, you've seen Amal."