xy chromosome

If Mary were impregnated, if you will, by God, how could Jesus in all respects appear to be a man with an evident XY chromosome pattern when God would, with some certainty, not be a man with the normative XY chromosome? If Jesus were to have the XY chromosome, which he most likely had (not only did he take human form but he also presumably functioned as a man would, at least as intimated by the Bible),why would not impregnation by a mortal have been as appropriate?