A study released by the California Parenting Institute Tuesday shows that every style of parenting inevitably causes children to grow into profoundly unhappy adults. 'Our research suggests that while overprotective parenting ultimately produces adults unprepared to contend with life's difficulties, highly permissive parenting leads to feelings of bitterness and isolation throughout adulthood,' lead researcher Daniel Porter said. 'And, interestingly, we found that anything between those two extremes is equally damaging, always resulting in an adult who suffers from some debilitating combination of unpreparedness and isolation. Despite great variance in parenting styles across populations, the end product is always the same: a profoundly flawed and joyless human being.' The study did find, however, that adults often achieve temporary happiness when they have children of their own to perpetuate the cycle of human misery. 