Bathing with child of opposite gender

Very occasionally my husband gives our newly 2 year old daughter baths, and she likes when we come in with her. He recently took a bath with her with his boxers on because he said he felt more comfortable. I guess she wants to look at and touch his penis out of curiosity of course.

My question, is it inappropriate in general for a husband to bathe naked with his daughter at this age or vice versa? Are we doing her a disservice by not also teaching her boy body parts? Idk, what are your opinions in general