In the opening scene at the ballpark, the base runner has a decided limp because he pulled his hamstring on one of the first dozen takes of the shot. The shot in the film is one they settled on after approximately 20 takes, due to the fact that the hitter was unable to hit the ball into center field. The hitter was a college player, not a professional as originally dictated to the casting department.
The movie was filmed in central and northern Florida. The shopping center where the photo booth is standing is in College Park, Florida. The photo booth was constructed for the movie. The Showbiz Pizza is located in Altamonte Springs, Florida and is still there, except it is now (like all Showbiz Pizzas) Chuck-E-Cheese. Kevin's birthday party was filmed at The Mystery Fun House in Orlando, Florida.
When Grandma (Helen Shaw) inhales the helium balloon and says that when she was born, Grover Cleveland was President. Shaw was born on July 25, 1897, just four months and three weeks after the end of Cleveland's second term.
In the scene where Steve Martin and Mary Steenburgen are fighting over the fact that she is pregnant, Steve says "...Let's just have a dozen and act like they are donuts." In the movie Cheaper by the Dozen he plays the father of a dozen children.
In the scene where Gil and Karen are going to Kevin's school to speak to the school principal, the school is 'Gerald Paris Elementary School', named as an homage to Jerry Paris, who directed 42 episodes of Happy Days.
According to the interview in the DVD extras with composer Randy Newman, the soundtrack song "I Love to See You Smile", which is perhaps his most beloved, was written with Mary Steenburgen's smile in mind.
Martha Plimpton was bald at the beginning of filming because she had just finished Silence Like Glass in which she played a cancer patient. She wore a wig throughout filming and a hairpiece when Julie has a mohawk.
This movie was made into two different television series: "Parenthood," which starred Ed Begley Jr., Jayne Atkinson, and a young Leonardo DiCaprio and was canceled after only 12 episodes in 1990; and "Parenthood," starring Peter Krause, Lauren Graham, and Dax Shepard, and which started in 2010 (and is still on the air as of November 2012).