The genealogies of Christ as given by the Gospel afford one much difficulty. If Jesus was not the son of Joseph, why is His genealogy traced through Joseph?

The Catholic Answers

Jesus was not the natural son of Joseph. But Mary, who was the Mother of Jesus, was related to Joseph, whose genealogy was also her own. It was a Jewish custom to record descent only through the male line.

Radio Replies Volume 1 by Rev. Dr. Leslie Rumble MSC and Rev. Charles Mortimer Carty