There is no way where you can decide the sex of your baby. It is spontaneous and decided by god. The only thing what people do is get early fetal sex detection and abort if female but sex detection is banned in India.
I would suggest you should not bother about the sex of your baby instead be happy with what you have. As you mentioned your wife is a known case of hyperhomocystinemia and factor 5 leiden deficiency, all of which make her high risk case for pregnancy
besides having obstetrical risk factor of 2 casserean sections. With so many risk factors , ideally she should not plan a third one just for the sake of male child as no one can guarantee this. There is no treatment which makes a female conceive only male child.