Twelve percent of women will develop invasive breast cancer during their lifetime. A quarter million new cases are diagnosed each year. Many will go through chemotherapy and/or have breasts removed. It will still kill around 40,000 women a year (~14% death rate).
Women who give birth in their teens through early twenties have the lowest risk of developing breast cancer. The more children they have—and the earlier they have them—the better. Paradoxically, women who give birth for the first time in their 30s actually have an increased risk.
Cancer risk goes up while on the pill. Cancer risk declines with breast feeding.
By promoting delayed (or no) marriage and having fewer (or no) children feminism literally harms women.
Feminists will often state that banning abortion would harm women’s health. About 700 women die each year as a result of pregnancy or delivery complications. This is two orders of magnitude less than the number of deaths due to breast cancer.
Consider a pro-family society where abortion is banned completely and men and women marry and start families in their teens and early twenties. Even a small percentage decrease in breast cancer due to this would result in significant health benefits to women.†
It is often best to cite the evidence presented by your enemies and use it against them. This limits your bias and increases the strength of your arguments. If you read some of the links above, you’ll notice the well-cited claim that abortion (probably) does not increase the cancer risk compared to all women (and those who have miscarriages).
This really tiptoes around the core issue: abortion means a woman does not have a full-term pregnancy and birth when she otherwise would have except for abortion. Thus the woman who aborts is voluntarily not receiving the protective benefits that come with giving birth and breast feeding—benefits that would have happened if not for the abortion.
She should be compared to the women who give birth, not all women in general and not women who have involuntary abortions (miscarriages). If this is done, it becomes plain that abortion intentionally increases her risk relative to what it would have been if she had not gotten an abortion.
Feminism truly is the Religion of Death.
† When a woman dies from breast cancer, it was the cancer that killed her. When a woman dies from complications due to pregnancy, it is not the pregnancy that killed her, but the various complications. So you can save lives directly be decreasing cancer, but you can’t directly increase or decrease pregnancy complications by changing the number of pregnancies. Other factors are at play that prevent direct, immediate causation.