My sister in Law (my wifes elder sister), lost her husband earlier by an accident, after few months her 3 year kid very attached to me. We have no kids at that time. Because we just 1 yr after marriage. So her family and our family decided to live her with me. After 2 weeks we decided to marry and we married. Now we all together living, they both (wife and her sister) love each other alot and we do sex together too. Now i have a kid from my first wife. Her sister want a kid from me. So is there any problem to make her pregnent, my wife is ok with that. (I am 28 yr, my wife 24 and her sister 28yr)