No, I think you would have to wait until after the baby is born to get a DNA test. Until then try to be civil with your ex to prevent any type of drama once the baby is born.

Well it really depends on the guy. Guys are similar to women, they all have different taste.  I'm sure there is something special about you that a guy will find attractive. Just be yourself and also comfortable and secure with yourself. Most men love a woman with confidence.