[throwaway2245]

I think it depends (similar to other comments):

Either, you are engaging the kid's own personal interest in the thing, which has the potential to grow independently of you as a parent,

or, you can demonstrate your personal interest, at a stage while they are particularly fascinated with you - this, they will grow out of.

[polka_haunts_us]

A great deal of that probably comes down to how much you respect/like your parent. I think both my sister and myself resemble our dad far more than our mom, and our mom definitely demonstrated her personal interest onto us. My dad in comparison, while not really engaging with our interests, certainly didn't actively try to get in their way like my mom did.