While smoking does not affect fertility in males, it does affect fertility in females. It took 50-70 percent longer for female smokers to conceive than it did for female nonsmokers. The birth weight of a baby born to a woman who smoked during the pregnancy is considerably lower than the birth weight of a child [...]

Of course, this is not to say that we can’t identify some of these factors. The immune system can be weakened by other illnesses, poor nutrition, some drugs, some infections, stress, old age, cancer itself and some rare inherited disorders. Very active cancer cells can just develop by chance, but the more mutations that are [...]