The moment fertilization occurs, your baby is born. Remember, it is only a group of cells at first that later differentiate into an orderly figure ( we all were), but those group of cells have life. It is up to you to decide whether you wish to continue with that. At 4 weeks of pregnancy
, the yolk sac
, the future fetus, just forms and you can see it in high resolution sonogram. Please discuss with your partner and decide. Good luck.