My mind went to "A fairly typical household where grandpa/grandma lives in the house and you also have at least one baby, or someone (maybe same grandpa/grandma) have troubles digesting food". Funny how different our casual links can be formed in our head :)

It is more likely that the person purchasing adult diapers and baby food is the caregiver of an adult. Perhaps of themselves, or an aging parent, or their spouse who is recovering from surgery.

Note that there is a certain level of arbitrariness involved in this association game. For instance, if a household regularly is in need of both parsley and also condoms, the fact that they are purchased together may be a result of the pure coincidence that both were empty/used up at the same time (which is also a function of the package sizes of both items). We would be much less surprised at the mined associations if we took a longitudinal, per-household look.

Furthermore, a shopping basked is per-household, but not per-person: the parsley and the condom may be used by different members of the household, or be shared, or be part of a gift to someone outside.

The human brain also tends to make up "causal" connections between any two items, when the real reason is often much more mundane.