breast cancer. The statistician who collaborated with Brind later stated of their findings: "I have some doubts. I don't think the issue has been resolved. When we were talking about the conclusions, he [Brind] wanted to make the strongest statements. I tried to temper them a little bit, but Dr. Brind is very adamant about his opinion." Brind's paper was criticized in the Journal of the National Cancer Institute for ignoring the role of response bias and for a "blurring of association with causation." The amount of attention the study received prompted a cautionary editorial by a JECH editor. With the appearance of larger studies contradicting Brind's finding, Brind failed to convince the scientific community that abortion caused breast cancer. In 2003, Brind was invited to the NCI workshop on abortion and breast cancer, where he was the only one to formally dissent from the workshop's finding that there is no link between the two. Brind blames the lack of support for his findings on a conspiracy, arguing that the NCI and other major medical organizations are engaged in a "cover-up" for the purpose of "protecting the abortion industry". Proposed mechanism In early pregnancy, levels of estrogen, progesterone, and estradiol increase, leading to breast growth in preparation for lactation. Proponents speculate that if this process is interrupted by an abortion or miscarriage—before full maturity (differentiation) in the third trimester—then more immature cells could be left than there were prior to the pregnancy. These immature cells could then be exposed to carcinogens and hormones over time, resulting in a greater potential risk of breast cancer. This mechanism was first proposed and explored in rat studies conducted in the 1980s. Breast tissue contains many lobes (segments) and these contain lobules which are groups of breast cells. There are four types of lobules: Type 1 has 11 ductules (immature) Type 2 has 47 ductules (immature) Type 3 has 80 ductules (mature, fewer hormone receptors) Type 4 are fully matured (cancer resistant) and contain breast milk During early pregnancy, type 1 lobules quickly become type 2 lobules because of changes in estrogen and progesterone levels. Maturing into type 3 and then reaching full differentiation as type 4 lobules requires an increase of human placental lactogen (hPL) which occurs in the last few months of pregnancy. According to the abortion–breast cancer hypothesis, if an abortion were to interrupt this sequence then it could leave a