Prohibit gay couples from adopting kids

I saw a gay male couple on the game show "Limitless Win" trying to win a lot of money so they could adopt a child. This upset me because I strongly believe that this would be bad for the child.
A child needs a mother AND a father. They both have different roles. If a child has 2 mothers then who is going to do the father's roles? If a child has 2 fathers (like this poor child who the couple on Limitless Win are going to get) who is going to do the mother's roles?
A child with gay parents could even get bullied at school.
This could also make the child think that being gay is natural and The Bible condemns homosexuality.
So for the sake of children I think only hetrosexual couples should be allowed to adopt.