Is there a condition where two races can't have a baby ?i've had four miscarriages with a person from another race and one live birth with a person of my own race. i am 6 weeks pregnant now.

No: It's possible that the specific person you were trying to get pregnant with wasn't compatible with you, meaning that when your chromosomes combined, there were problems with formation of viable pregnancy. Also possible that he was cause for infertility (men are 30% of time) and not you at all. But none of this has anything to do with race.

Not aware of it: Miscarriages are actually rather common and estimated to occur at least 1out of five pregnancies. Since you have one live birth, even though it was with someone of same race, it proves you are fully capable of having a successful pregnancy. And now you are pregnant again, so thismismno fertility issue. Why you has four miscarriages with a man of another race, i can't explain.