Number 2 says research showed that "the more there was gene similarity between people the more they fell in love". That is backwards from reality. Since the late 70s some studies have indicated, possibly, that mammals tend to choose mates who differ most in major histocompatibility complex (MHC) genes. The MHC system tells our immune system which cells are us and which are invading germs or parasites. Arguably, greater variety in MHC genes leads to greater disease resistance.
This series was Americanised for profit. The series was made in the 60's in Wales and had a location that America could not hope to emulate.