A recent study by the scientists from University of Copenhagen informed that women whose first issue is a boy suffers from miscarriages more often than mothers who gave birth to baby girls. It states that male genes can provoke immune reactions in some women, preventing normal carrying of pregnancy. Henrietta Svarre Nielsen, research’s guide states, ‘It’s known, that carrying a male fetus affects a woman’s immune system. During 22 years after a woman gave birth to a boy, it’s possible to find immune cells, directed against male cells, in her blood’. According to Nielsen, immune reaction, directed against male fetus, increases little by little and starts spreading on girls too. Consequent upon which, habitual abortion and inability to give birth results.