Fertilization is the union between the egg and the sperm. For this, it is necessary that the sperm has great energy and is able to pass through the egg. Otherwise, the sperm will not be able to fertilize the egg and, therefore, pregnancy will not occur.
Men who smoke marijuana have altered sperm quality according to several studies. This drug causes a decrease in the energy of the sperm, which complicates the penetration of the egg for fertilization.