Robert is a pedo-endocrinologist, probably the best in town. In his private life, he comes from a long line of naturists, all the way to the FKK in Germany, many generations ago.
In his ideal, he would live in a naturist resort, but Anna has a limit of nudity she can tolerate.
How did they become a naturist or what is their relation to naturism?
Robert is from a long line of naturists, he married Anna, who seemed to want to become one.
When they had Clark and became close to Lisa and Jake, however, his wife became colder, more distant and with it, nudity at home vanished.
Still, when he is alone, he is nude. And later, Clark and him had an understanding to be nude at home when they were alone, but never to mention it to Anna, or Lucy, out of fear it would end.