Complex sentence: Bergler denies that homosexuality has biological or hormonal causes, and also rejects the idea that it is caused by the Oedipus complex or having a dominant mother and a weak or absent father, which he describes as outdated.
Split into simpler sentences: Bergler denies that homosexuality has biological or hormonal causes, and also rejects the idea that it is caused by the Oedipus complex. He describes the idea that having a dominant mother and a weak or absent father causes homosexuality as outdated.