siblings

(Newser) - An identical twin separated at birth from her sister in a hospital mix-up and reunited by a fluke 28 years later is suing Spanish health authorities, reports the Times of London. The mistake didn't come to light until one of the sisters walked into a shop run by a friend...

(Newser) - A team of Chicago-based scientists is conducting a large-scale study of gay brothers to learn more about the genetic factors involved in sexual orientation. Similar studies have been too small to be conclusive; this time, scientists recruited 1,000 pairs—10 times the size of previous studies— to contribute DNA...

(Newser) - In the wake of the study released last week on intelligence and birth order, parents and social scientists are scrambling to explain why firstborns score an average of three IQ points over subsequent children. Theories range from the role older children play as tutors to younger sibs to the notion...

(Newser) - Big siblings have long suspected it, and now science backs them up: Oldest children have slightly higher IQs than younger kids. Family dynamics, not biological factors, account for the 3-point discrepancy, which holds up for children who become the oldest after the firstborn dies. That tiny gap may mean the...