MINNEAPOLIS—Two years after his discovery by a team of developmental psychologists, David Sullivan, a man raised by a pair of mated parents, is still struggling to adapt to normal human society, sources confirmed Friday.

According to researchers at the University of Minnesota, Sullivan, 25, has made significant progress since moving into his own apartment in 2009, but the decades he spent being reared by parents has made joining civilization a desperately difficult task.

"The chances of David ever becoming socialized to the point where he can function normally among humans is very slim," said Dr. Lisa Reynolds, a psychologist who has observed Sullivan since he was first introduced into the real world. "The sheltered, isolated environment in which he spent his adolescence has left him completely unequipped to deal with modern life. Tasks that may seem simple to us, such as doing laundry or grocery shopping, completely baffle David."

Reynolds explained Sullivan's assimilation into society had been hindered to a large extent by his extremely limited communication abilities. Though he has learned basic takeout-ordering commands, he will often relapse into the grunts and mumbles he is believed to have learned from the male parent, and will occasionally emit a high-pitched whine when he does not receive something he wants.

Sullivan reportedly has trouble navigating even the most simple situations, often becoming frustrated to the point of tears by an attempt to mail a letter at the post office, or shutting down completely when forced to have a conversation with a person he doesn't feel comfortable with.

"Whenever David enters a social gathering, for example, he quickly becomes fearful and anxious," Reynolds said. "He'll back himself into a corner, rapidly consume alcohol and snack foods, avoid eye contact, and, in some cases, lash out with sarcasm in reaction to perceived threats. Within an hour, he invariably becomes spooked and flees."

When he feels especially threatened or overwhelmed, Sullivan returns to the place where he was raised, sometimes spending an entire weekend in the habitat to which he is still best adapted. According to Reynolds it is, in many ways, the only world Sullivan understands.

"David's lack of acculturation is particularly evident when he attempts to interact with women, even in the most innocuous of circumstances," Reynolds said. "Most likely he was fiercely protected and coddled by the female parent during his teen years instead of gradually learning to interact with girls as a normal child of that age would."

"Sadly, David remains so off-putting to members of the opposite sex that he will probably never procreate," Reynolds added.

Though Sullivan continues to struggle, experts who have observed him were quick to point out that the parent-reared man has made tremendous progress considering how much of his life he spent in an environment where his every need was anticipated and met.

"In the beginning, he could barely sit down in a restaurant and use a knife and a fork," said behavioral psychologist Peter Erskine, adding that it took Sullivan months to finally stop wearing the same tattered, foul-smelling Minnesota Vikings sweatpants every day. "He was only interested in foods covered in ranch dressing or barbecue sauce, and if there was a buffet involved, he would walk up to it and begin eating right out of the trays."

"He still sometimes loudly chews with his mouth open, and he spills on his shirt more often than we'd like, but it's now possible to get through dinner with David without being completely revolted by his presence," he continued.

Erskine added that in therapeutic settings, Sullivan has been extremely useful in helping those suffering from difficulties similar to his own, such as 28-year-old Brian Werner, a man who was raised by television.