Character mistake: When Alex mentions to Mallory that he's had sex before, he tells her he was 17 and that it was leap year. Not correct, this event occurred in 1982 (during one of the first episodes when Alex was 17), which was not a leap year.
Character mistake: When Uncle Ned calls Alcoholics Anonymous, he only dials 6 digits on the phone (instead of 7), but still the call successfully goes through.
Answer: A scene very similar to the one described happened on the show Mr. Belvedere that was on in the same time frame as when Family Ties was on. Perhaps this is what you are remembering.
af4dable ★