Everything Is Gendered
Gender fluidity was not talked about much in the mainstream culture while Boomers were growing up. A large majority of them always gender everything. Blue for boys, pink for girls. Dresses for girls, button-ups for boys. The list goes on. You should always half-expect your Boomer relative to get your daughter something princess-related despite throwing her a car-themed birthday party.
Dry Toast?
What's the best thing since sliced bread? Dry toast, of course! Jokes aside, it's apparently a common trait among Boomers to enjoy dry toast. No butter, no jam, no egg... Just toast.