Asian women = child women? If that's not outright racist and/or ignorant, I don't know what is. And I'm not one to get offended when it comes to issues relating to race.
It's not necessarily racist or ignorant. There is a difference between analysing social trends, generalising about them (necessarily), and being racist. Of course, a simple comment like Gustavo Kuerten's can be interpreted as a huge generalization, saying Asian women all look like children, etc... That would be overgeneralizing, sure. But there is a reason why Asian women are perceived this way, and it's not just linked to racism.
Look at Western magazines and the conception of beauty that they market. If that's not a childlike conception of beauty, then I don't know what is. That's mostly true of Japan but from what I saw of Korean magazines, it was pretty much the same. The Japanese vision of erotica, for Westerners, often looks shocking because it almost seems to market paedophilia. The religion of everything "kawai" is definitely linked to the idea of the child-like woman being the sexiest type of woman.
That's also becoming true in the West. The aversion for body hair, for instance, is one example of how we tend to eroticize child-like bodies more than "mature" bodies. Other examples include the "lolita" trend, horrors like beauty contests for children, or simply the religion of being "skinny" which tends to bring ideal bodies further away from what is considered a "real" woman's body (that's to say, a body which has all the attributes you link to puberty, bigger breasts, bigger hips, a big waist/hip ratio, etc).
And yes, it's true that in general ("in general" is the key here...), Asian women tend to look younger, be thinner, and have less "curves" than we do. Moreover,they are also encouraged by their culture (at least in Japan) to "act" younger if they want to be sexy. So they often correspond more to the "child-like women are sexier" ideal.
Now, if Verdasco's girlfriend definitely corresponds to that, that's obviously not true of everyone. That's why I posted a picture of Gong Li who is an example of a gorgeous Asian women who has curves and does not look childlike at all.
BTW I'm not saying that liking child-like women is wrong, and liking curvy women is right. I'm just explaining why some people might react like Gustavo Kuerten and have the feeling that the reason why many people love Asian women, and why he doesn't like them, is that their appeal is often linked to their being "child-like".
(Also, I don't think that the appeal of Asian women for Westerners is based exclusively on that, but it is definitely a social trend that exists, it is not just a fantasy based on racist prejudice)