First of two consecutive pictures where actress Diane Keaton played a mum. The subsequent film was The Good Mother (1988). That other movie was directed by Leonard Nimoy who directed 3 Men and a Baby (1987) which was first released in the same 1987 year as Baby Boom (1987).
"It's played like a '40s comedy" according to Time Out. The picture was inspired by such 1930s and 1940s era comedies as Bachelor Mother (1939) and Woman of the Year (1942). The production notes for this picture stated that films from the 1930s and 1940s were used as a model for the movie. Writer-producer Nancy Meyers once said: "I always loved how Roz Russell [Rosalind Russell] and Katharine Hepburn portrayed working women. They wore wonderfully tailored suits, and always carried envelope bags under their arms as they walked through their offices dishing out orders".
As Elizabeth was the child of J.C.'s "mother's cousin's daughter's son" (Andrew), it is very unlikely that they would have the same last name, as mentioned when she is reading the will.