I want to know whether it would be more effective for a male or female to learn Attract.
male is more common so female is the better choice. More boys play pokemon than girls and boys tend to prefer there manly pokemon to be... well... uhh...men.
Females are better at using attract than males. A lot of Pokémon have a higher chance to be male than female. Granted, there will still be female Pokémon out there.