Why we love specialy grls or boys in teenage?

There is no any scientific reason behind love... u just get attracted towards the opposit sex, since u grow older all ur harmons starts to activate and tats new for ur body, so u feel like loving some one, and atlast you have sex tat's all, love is nothing but a wish to have a sex k... so first u find the scientific reason behind ur poor english ,later u think abt love... gud luck