It's a boy..

A middle-aged couple had two beautiful daughters but always talked about having a son.
They decided to try one last time for the son they always wanted.
The wife got pregnant and delivered a healthy baby boy.
The joyful father rushed to the nursery to see his new son.
He was horrified at the ugliest child he had ever seen.
He told his wife, "There's no way I can be the father of this baby.
Look at the two beautiful daughters I fathered! Have you been fooling around behind my back?"
The wife smiled sweetly and replied, "Not this time!"