I showered with my father when I was wee one, actually when my Mom was in the hospital, giving birth to my sister.
I was two and a half and I remember pointing to his private area and asking him what it was. He never put me in the shower with him again.
Every parenting book I've read has said about the same thing...that the age that children start to become aware of nudity is typically around age 3.
In our household, this has rang true. My husband has never bathed or showered with our children but I've bathed with my oldest and at around three years old, she started to point and ask questions. I answered her questions honestly and ceased to bathe or change around her.
I've been interrupted while trying to get dressed. I politely explain to my children that Mommies need their privacy.
Once Emmie started asking questions about the body, I informed her that our body parts belong to ourselves and people shouldn't touch our body parts and that we should keep our body parts to ourselves.
Every kid is different. Emily is quite inquisitive as I was at an early age. My two year old isn't as inquisitive as her sister was at this age.
Every parent is different as well.
I wouldn't have felt comfy at all bathing with a son. And my hubby would never bathe or shower with the girls.