Using an alias when getting girls

my best friend has another set of friends in a different town, when he goes out with these friends its usualy to clubs, he has told me that whilst out trying to get girls he uses a differnt name and tells the other friends to call him it, he says its so he can have one night stands with girls and not use a condom, because they know the wrong name, they cant trace him (facebook etc), im concerned that this is morally wrong, what if he gets a girl pregnant? i spoke with him about it but hes not bothered, he says he had an uncontrollable desire to spread his seed and he had indeed had sex with over 40 girls, i just think his actions are wrong