A man’s smoking and drinking do not affect the birth of a boy or a girl. The birth of a boy or a girl is determined by the sex chromosomes provided by both parents, such as the mother’s X chromosome combined with the father’s X chromosome will give birth to a girl, such as the mother’s X chromosome combined with the father’s Y chromosome will give birth to a boy. Smoking and drinking does not affect the type of chromosome provided by the father, nor does it affect the sex chromosome combination, so men who smoke and drink do not affect the birth of a boy or a girl. It should be noted that men smoking and drinking can change the body’s internal environment, affecting the quality of sperm, and in serious cases can lead to weak sperm, oligospermia, etc., affecting the reproductive function, men should not smoke and drink during pregnancy preparation. In addition, couples with fertility needs should consult a medical professional, scientific preparation for pregnancy, so as not to lead to adverse consequences.