Even if we imagine that Maria was Jewish (which is higly unlikely according to political and demographical situation in Galiliea of that time), every Crhristian will be only proud to believe in God that is so allmighty, that he could put itself into and create a good person even from a Jew. Moreover, since other Jews did not accept that divine change in one of them, they are even worse than just religious intolerant xenophobs, they betray their man in exchange to ability to continue their business. It is much more disgusting.

So, it will be much better for Jews if they would not try to pose Jesus as Jew. :)