Captain David Moulton, a Navy psychiatrist, told the court that Manning's facial features showed signs of fetal alcohol syndrome.
Manning's father remarried in 2000, the same year as his divorce.
His new wife, also named Susan, had a son from a previous relationship.
Manning's older sister, Casey Manning, was born in 1976.
The couple returned to the United States in 1979, settling first in California.
Manning had come out to two friends in Oklahoma as gay, but was not open about it at school in Wales.