Here's the summary for the wikipedia article you mentioned in your comment:
Forced fatherhood or imposed paternity, occurs when a man's semen is used, against his will or without his knowledge or consent, to inseminate a woman, it includes deception by a partner about their ability to get pregnant or use of contraceptives, birth control sabotage, and sexual assaults of males that result in pregnancy. "Sperm theft" (also known as "unauthorized use of sperm", "spermjacking" or "spurgling" (a portmanteau of sperm and burgling), refers to a specific form of forced fatherhood where a males semen is collected without his consent. Although the term uses the word "theft", it more closely falls under a state of fraud or breach of contract. Stealing of sperm in itself without using it for successful insemination is not illegal and is difficult to prove. It usually has no bearing on issues like child support.