Nick and Shelly Stevens, a boy, Henry Pierce, Dec. 16, St. John’s Hospital, Santa Monica.Father’s senior agent for United Talent Agency; mother is non-pro. Thania and Tony St. John, twin girls, Liza and Lexi, Oct. 21, St. Joseph’s Medical Center. Mother’s producer of Warner Bros. Television’s “Life Goes On”; father is a free-lance cinematographer. Stephen London and Michelle Katz, a boy, Joshua London, Dec. 7, Cedars-Sinai Medical Center. Father’s a teacher and freelance screenwriter; mother is general counsel MCA Merchandising. Wendy Schenker and Ron Fish, a boy, Ryan Adam Fish, Dec. 18, Cedars-Sinai Medical Center. Mother is an actress. Father’s non-pro.