After purchasing the rights to the book the film was based on, Lucille Ball became very close to the Beardsley's and even went as far as to treat the whole family to a vacation at Disneyland.

Tim Matheson and Jennifer Leak (who played the eldest children) met while filming the movie and dated for one year. They married on Sept. 28, 1968 but divorced in 1971.

Helen and Frank met a little differently than in the movie. In her book, "Who Gets The Drumstick?" after Helen moved to San Francisco, she wanted to honor her dead husband's wishes by enrolling her children in parochial school. She finally found a school run by a nun, Mother Superior Sister Mary Eleanor. As she was enrolling her children in the school, Helen told Sister Mary that she was a widow with eight children. Sister Mary then confided to Helen that she has a brother with ten children who recently lost his wife to complications from diabetes. Helen asked Sister for Frank Beardsley's address and she sent Frank a copy of a prayer that she clipped out which gave comfort on dealing with a loss of a spouse. Encouraged by her brother and sister, Helen went on a batch of unsuccessful blind dates. When a friend's husband died, Helen wanted to send her a copy of the prayer that she sent Frank. She wrote to Frank asking for a copy of the prayer. Frank sent it back and a correspondence immediately began between Helen and Frank which finally led to another blind date. This time sparks flew between them.

The wedding invitation used in the movie is the actual wedding invitation designed by Frank Beardsley, husband of the real Helen Eileen Beardsley. The children's names are listed in their real-life birth order.

The real Helen and Frank Beardsley had two children following their marriage: Joe and Helen.

Continuity

When Colleen and her boyfriend are eating lunch, at school (he's talking about the "freak-out") Colleen takes her sandwich out of the paper bag and unwraps it three or four times.

When the doctor examines Phillip (the first night all the family is together in the new house) he wipes and puts away his thermometer twice.

Mail sent by Frank while on the ship is addressed to 1034 Linden Ave, but at the end of the movie the house number on the front porch is clearly shown as 346.

In Van Johnson's first visit in the movie to the Beardsley house, the kids wipe their hands on his uniform shirt, leaving raspberry jam and indelible ink stains. First is the raspberry jam, then the ink, but when we see the front of his shirt after the ink is applied, we can't see the jam. In the very next scene, the shirt is spotless.



Factual errors

During their first date in a club, Frank is wearing his hat during the entire sequence. This would be a hideous breach of Naval etiquette, and never done by a real Naval officer.

When Frank goes to his carrier's flight deck to halt the launch of the mail plane, he is wearing a ship's ballcap. After packing, he returns to the flight deck wearing a combination cap. In fact, neither hat is permitted on the flight deck during flight operations, as they are easily sucked into a jet engine intake, causing foreign object damage. Further, no one is permitted on the flight deck without the cranial helmet, goggles, and hearing protection that we see the catapult launch officer wearing, except for pilots and necessary flight crew going to and from their aircraft.

When Frank learns that his wife is pregnant, he goes to the flight deck and convinces the catapult launch officer to stop the launch of the mail plane. In fact, the catapult officer does not have that authority. Unless there is a mechanical or safety problem, the Air Boss (who is never on the flight deck) is the lowest ranking person with the authority to cancel a launch.

When Frank and Darrel are talking about dating while they're standing near the airfield, they're both wearing lieutenant junior grade bars on their caps. Two such older career Navy officers should be higher rank than this. Also, the officer that Frank is giving orders to has full lieutenant bars. This officer outranks Frank.

Henry Fonda's character says that Fanny Hill was written in 1742. It was actually written in 1749.



Revealing mistakes

In the dispensary, when the scene freezes so that Van Johnson can talk to the camera, a bus can be seen passing by the window (at 37:14 on the DVD).

After the wedding the family moves in the new home. While the children are being assigned their rooms "Mike" is seen bringing suitcases upstairs. A couple of scenes later he is seen bringing the same suitcases upstairs a second time.

The letter from Helen to Frank and the letter from Frank to Helen are in the same handwriting.

When Mike (Tim Matheson) is walking down the sidewalk at the end of the movie in his Marine Corps uniform the tie, shirt and trousers are different shades of khaki, something a Marine would never do and he would be considered being out of uniform.

When Helen sees Darryl in the coffee bar, her eyelash is already in her drink (you can see it if you look in her glass) then someone bumps her it "falls off."



Miscellaneous

At the urging of her daughters who are trying to make her look more glamorous, Helen reluctantly agrees to wear false eyelashes on a date - although the actress who is playing her (Lucille Ball) obviously is wearing false eyelashes throughout the entire film, including scenes that occur long before the one mentioned.



Anachronisms

Lucille Ball gives birth in this movie, and she was 56 years old when the movie was made; Fonda was 61. Both of them would die at age 77.



Crew or equipment visible

The reflection of a cameraman is visible in the window of the school bus as it drives off.



Errors in geography

Driving back from the Japanese restaurant, the trio are on the upper deck of the San Francisco Bay Bridge. The upper deck runs westbound, into San Francisco from the east. To return to Alameda, eastbound from San Francisco, one would drive on the lower deck. This was likely known by the filmmakers who used upper deck footage because it's much nicer than the tunnel-like experience of the lower deck. [Edit] in 1962, when the movie is set, there was still two-way traffic on the upper deck. The rails for the trains that used to run on the lower deck until 1958 were not removed until 1963, which is when the current traffic scheme (eastbound on the lower deck, westbound on the upper deck) was put into place.



Plot holes

Frank decides to call Helen, so he looks her number up in the white pages. But Helen had just moved to the city recently, so her number shouldn't be in the phone book yet.



Character error

When Frank decides to buy Helen a gift to commemorate their first and last date she picks a stature of Kwan Yin. The clerk says the Kwan Yin means "joyous symbol of fertility" (at 34:32 on the DVD). Kwan Yin actually means "Observing the Sounds of the World" and is primarily considered the Goddess of Mercy, Love and Compassion. Her fertility aspects are minor and would not be mentioned by a Chinese person.

When Frank is assigning rooms Helen says that Tommy should not sleep in the same room as Phillip while he has the flu. Despite priding himself on his organization, Frank then decides to make a mountain out of a molehill and disrupts several of the children's sleeping arrangements to relocate just one child.