Human Nature (2002)

Lila, a young woman with a severe hormonal condition, is forced to hide her malady and eventually leave society for the solitude she finds in nature. While in the forest she writes novels that become wildly successful. Once famous, she returns to society and starts looking for a man. With the help of her success and her therapist Louise, she starts dating Nathan, a repressed scientist who teaches table manners to mice. One day Lila and Nathan are hiking in the woods and discover Puff, a feral man who had been raised in the woods as an ape by his mentally ill father. Nathan decides to take Puff to his lab and, using the methods he developed with mice, transforms Puff into an example of elegance and education. Everything seems too good to be true except for the small problem that as soon as Puff gets a taste of freedom, he rushes out to visit prostitutes. While Puff is struggling with his sexual urges, Nathan discovers Lila's condition and falls in love with his French assistant Gabrielle.