Although to some people it may seem counter intuitive, many young men would rather have their mom see them nude in the doctor's office than their dad. Some boys feel that their dads would be more judgmental about their development than their moms would be.
Exactly! Since I was a late bloomer, I really did not want my dad seeing me naked until I “caught up” with the other boys my age – or at least to my brother who was two years younger than me and took after my mom's side of the family. In retrospect, that was the wrong thing on my part. I was the spitting image of my dad, so if he had been the one monitoring my development, he could have compared me to himself. (Meanwhile, my brother looked like my mom's brothers, with her practically raising the youngest while her mother was working, making her the best judge of my brother's development.) Not that my dad ever would take pediatrician duties – that was definitely a woman thing back in those days in the South, but he did try to have some naked time with my brother and me, and I refused.
We were at a party at his rich friend's house, and they had a hot tub on the patio, so we had brought swim trunks. After dinner, when we were supposed to go try it, my mom asked my dad to take my brother and me to get changed. We went to a spare bedroom with an attached bathroom, but when I went to the bathroom, the door was locked. My dad said someone must be using it, and we should just change there in the bedroom.
He proceeded to get undressed, and my brother followed suit. When he got to taking off his underwear, he said, “It's not much to see, but you boys should see it.” And basically he was exactly how I am now – definitely not a shower, and who knows if he was a grower, thought I sure am not. But to prepubescent little me, he still seemed huge. My brother, unfazed, followed suit, and it was clear at 11 he was further along than I was at 13. I've not seen either my father or brother naked since that night. But I stubbornly waited until the person got out of the bathroom, and I changed in there.
Joke was on me though, since that clearly was my mom's attempt to get the feedback my pediatrician wanted several months earlier when I turned 13 as to whether I was behind where my father was at that age. Since I didn't let it happen, and a few months later at my exam at 14, my doctor insisted that my mom find out whether I was behind where my father was, my mom then schemed to have me stay with my paternal grandmother for a night, where she ran a bath for me, and I had to let her see me naked for the first time in over two years. But as the doctor said my testicles had just started growing, and I was still completely hairless, she was seeing basically nothing new since I was 11. Now that I was taller and chubbier, my penis likely looked even smaller by comparison than she remembered.
She just smiled and said, “You don't need to be shy. You look exactly like your daddy did at your age, and he grew up just fine.” Clearly she passed that info along to my mom, and my mom relayed it to my pediatrician. At my exam at 15, while he had my undies down, showing my mom that I was starting to get pubic hair and that my penis was getting longer, he said I still was a couple of years behind, but at least was catching up at a normal rate like my dad did. The scheming to get me naked in front of my dad or my grandma stopped.
Again, though, had everyone just been up front with me about it, e.g., “Your puberty is behind schedule, but that's not a problem if the same was true for your dad, so either your dad or your grandma needs to see you naked to see if you look like your dad did at your age,” I'd have chosen Grandma in a heartbeat. I really didn't want my dad to judge me. I had no idea that he was the person most likely to understand what I was going through.