The trouble with all these theories is that they're really nothing more than personal opinions, no matter how well adorned with footnotes. Until recently, there's been little attempt to provide any actual hard data on the subject.
One study, recently conducted at Old Dominion University, in Norfolk, Virginia, provides one of the first attempts to fill in the gaps. Psychologists, Ph.D., and, Ph.D., asked 210 college students enrolled in a psychology course about their own exposure to parental nudity as children (up to 11 years old), how frequently they slept in their parents' bed as kids, about their parents' attitudes toward sex generally and about their own sexual development as adults.

Their conclusion: "The results suggest that childhood exposure to nudity and sleeping in the parental bed is not related to poor sexual adjustment. ... Indeed, it appears that parents who have a casual attitude toward family nudity and who permit their children to sleep in their bed may have children with better self-esteem and who feel more comfortable with their sexuality."
Dr.and Dr. go on to say, though, that exposure to nudity between the ages of 6 and 11 is "modestly related" to increased sexual activity later in life, for both girls and boys. Is that good or bad? Depends on how you look at it.

These investigators favor the view that sexual behavior that's unburdened by guilt, anxiety or sexual dysfunction, even if it's sometimes a little freer than society generally condones, is probably a good thing. (We're not talking about wild promiscuity here; none ofthe students, no matter what their childhoods were like, said they were particularly inclined to having casual sexual encounters.) Other parents no doubt would feel differently and so might be more inclined to cover themselves up in front of the kids.

Despite the dire warnings of other experts, the psychologists also found that (especially for boys) sleeping in the family bed was related to greater self-esteem and less guilt and anxiety. In fact, every single student who spoke of it had positive recollections about relatively casual nudity around the house and about family bed-sharing. Said one: "It always gave me a feeling of security to know that if! had a bad dream I could crawl into bed with my mom and dad."

The psychologists go on to point out that it's not really nudity or bed sharing, by themselves, that seems to lead to calm and happy sexual adjustment during adulthood - it's the whole attitude toward sexuality that permeates the household. "It seems," they say, "that the attitudes toward sex that the parents convey to their children may be more important to their subsequent sexual adjustment than any particular family practice."