I'll offer some degree of defense for Alex... although he's quite good at speaking for himself. First of all... he is but 19 years old and quite likely may not have yet come across a Black or Asian woman that he has found personally attractive. Growing up in a predominantly (almost wholly) White community, I don't think I would have entertained the notion of finding either a Black or an Asian woman attractive myself at that age.
I will go on to say that there is a degree of hypocrisy involved in this thread when one is asked for an honest response concerning what initially attracts us as individuals... and then when such honest answers are put forth, some are taken to task concerning their answers. Honestly, propriety and political correctness have nothing to do with what we are or aren't attracted to. The fact that Alex has isn't sexually attracted to Black or Asian women would seem to me no more racist than the fact that I have never been sexually attracted to men is sexist. Alex may be wholly respectful... even admiring of Black and Asian women in every other context, but simply finds that he has never been physically attracted to any of them. I suspect there are certain attributes that we all find unattractive to a given extent and as such are not attracted to individuals with these attributes. Obviously, this amounts to a prejudice or discrimination of a sort... but desire... attraction is nothing if not discriminating and propriety, equality, justice, and political correctness have absolutely nothing to do with it.
And in case some were wondering... in light of my defense of Alex... yes, I most certainly have come across more than my fair share of Black, Asian, and Hispanic/Latino women that I have found deadly attractive. One of my favorite operatic performers... and I'll admit that her appearance bears far more weight upon my admiration than her solid singing abilities... is the soprano, Danielle de Niese, who is of Sri Lankan Burgher heritage... a Eurasian ethnic group, historically from Sri Lanka, involving a mixture of European and native Sinhalese:
http://www.youtube.com/watch?v=P7onnt2OvPY