I'm perfectly comfortable being naked when alone with DH, or in the ladies' changing rooms at the swimming baths.
When I was a child we were often naked at bath time or bed time in the presence of our parents or nursemaid, but never in front of others.
If my adult son catches a glimpse of me naked, or I of him, we don't worry about it, but we don't bath together or sunbathe nude. DIL? well she's a woman, so I wouldn't mind her catching a glimpse of me in my birthday suit, but DH be mortified if he saw her naked, or she him.
We wear night clothes when there are children staying in the house, but not otherwise.
Obviously, a nurse would have to see me naked if the day comes when I need help bathing or dressing. I can't imagine when a doctor would need to see one completely naked, except at a post mortem.