What were the customs in Jesus’ day for young Jewish people regarding courtship, engagements, and physical intimacy before marriage? What about any children conceived or born before the wedding?
In the United States today, you don’t hear the word betrothal very often. In Jesus’ day, however, this was an ordinary part of the marriage process. The future husband and wife publicly declared their intention to marry at some future date. Many more marriages were arranged by the families of the bride and groom than are arranged in the United States today.
When St. Joseph learned that Mary was pregnant, and he knew that he was not the father of this child, he had three options: 1) denounce her for adultery, 2) write a bill of divorce to dissolve the betrothal and free Mary to wed someone else, or 3) follow through with the wedding. He chose the third possibility after he learned in a dream the real story about Mary’s pregnancy (Mt 1:18–25). If he had wanted to, he could have accused Mary of adultery, which, according to the law of Moses, was punishable by death for both parties.
Jews considered children conceived during a couple’s betrothal legitimate heirs. Pagan laws would not challenge that if the father recognized the child or children as his own. That is what St. Joseph did for Jesus although he was not the Messiah’s biological father.