theres noway to answer that. theres more to being hispanic and catholic, it really depends on the person

I wasn't aware one could "go" Muslim, or any other religion for that matter.

Perhaps because the percentage of hispanics that are catholic are much higher than any other religion within the ethnicity, it has become more of a cultural thing than a religious thing. If it has become more cultural, then one is less likely to think about the truth or lack there of behind it, and thus less likely to make such a dramatic conversion away from it (i.e. going muslim rather than lutheran, or something like that). But it's really not my place to say. It depends on the person in question more than anything.

Depends on the person and how religious they are and their family is

I think you have to take this on a case by case basis. There are many factors for why someone changes religion, not only ethnicity.

I don't know what you mean by "naturally catholic". I understand Catholic by birth, meaning born to Catholic parents, and Catholic by choice meaning someone who has chosen to become or remain a Catholic. A recent high profile example of the latter is the last PM of UK Tony Blair who on leaving office announced that he was becoming a Catholic. If one is convinced that one's faith is the best of all faiths out there then the likelihood of change is negligible. If however one comes across any information from within oneself or from others that challenges that conviction then the likelihood begins to increase. Amazingly enough everyone has their own individual story. Here are just three examples. In the first video we have a former Catholic priest explain his journey in a tv interview which is in English, despite the introduction being in Arabic. The next video is of an ex nun telling her story in Malay with English subtitles. There is a video clip looking into the conversion of Latinos but unfortunately it is not in English and has no subtitles it might shed some useful light on your question if you can understand the language you'll find it at http://www.youtube.com/watch?v=j2w14xxi0bM The Catholic American woman in the third video says she converted because she was seeking a closer relationship with God. .

If his girlfriend is hot and muslim, then yeah, there`s a likelihood.

That all Hispanics are Catholics is a generalization. Most, maybe, but not all. My husband is full-blooded Latino, and he is Presbyterian. The liklihood of one converting to Islam just depends on the person, I suppose.