Differential exposure to testosterone levels while in utero can affect behavior later in life.
Male rodents surrounded by two females in utero (2F) act relatively "feminized": they exhibit
decreased courtship behavior with the opposite sex and increased parenting behavior
(help their parents care for young).
These behaviors are also correlated with circulating levels of testosterone, thus this hormone plays a
proximate role at two levels of causation.
Intrauterine position.