A study released Thursday by sociologists at the University of Michigan has found that 90 percent of the biological parents of adopted children ages 6 to 12 are millionaires who own sprawling mansions with huge backyards. According to our data, nearly all parents who once put their children up for adoption now own luxurious estates with vast grounds that include an Olympic-sized pool, a stable for ponies, and big tree houses that have all the latest video game consoles hooked up to giant TV screens, said head researcher Joren Offerman, adding that a vast majority of the biological parents were professional basketball players, astronauts, or royalty. Nine in 10 of these parents have apparently struck it rich, willing to pay for unlimited trips to Disney World, all the coolest clothes, exotic pets such as boa constrictors and giraffes, and destination birthday parties in Hawaii at which everyone invited arrives by private jet and there are live appearances by performers like One Direction and Katy Perry. The study concluded that every night, the parents lie awake in bed, thinking about the children they gave up and how much they love and miss them. 