Why Are Boys Fond Of Girls?

Boys genetically are fond of girls due to survival of the species.  There can be many variations to different attractions, like genetics, but in general, males need to plant their seeds, as they say, in order to make sure that there are offsprings to continue on the race.  Human race is what I mean.  Males will seek out more females, while as females, naturally seek out better makes to ensure better offsprings i.e. Stronger as well, males who will be there to help provide