The word “nothing”, represented by the number “0”, was another reference to the female genitalia. Romeo abruptly interrupts Mercutio perhaps because he is uncomfortable with Mercutio stating that casual sex can lead to pregnancy  (“prick love for pricking”).

This may also have been uncomfortable for Shakespeare. When he wasn’t much older than Romeo, he had an affair with Anne Hathaway which resulted in an unintentional pregnancy. After a hastily arranged marriage, Anne moved in with Shakespeare and his parents. Three years later Shakespeare left Anne and three infants with his parents and moved to London. The couple would not live together again until Shakespeare retired 30 years later.