Nulliparous Plaintiffs, Fault and Causation
It has been known for a couple of decades now that women who never have children (i.e. women who are nulliparous) and women who do have children but not until they are 30 or older suffer a striking increase in their risk of developing breast cancer. The evidence for the association between never giving birth or delaying having a child continues to accumulate and now it appears that the increased risk is focused on hornmone receptor-positive breast cancers. See "Associations of Breast Cancer Risk Factors With Tumor Subtypes: A Pooled Analysis From the Breast Cancer Association Consortium Studies" in the current issue of the Journal of the National Cancer Institute. So let's say you've got a nulliparous plaintiff alleging that your drug or device or chemical caused or accelerated her hormone receptor-positive breast cancer; how do you handle her status?
The first problem a defendant faces in such a case is the risk of inadvertently wandering into the minefield called "blaming the victim". The plaintiff has either freely made a choice or has tragically been unable to have a child. Either way the jury will react strongly and negatively to any discussion about parity status and causation that makes even the slightest trespass into the issue of fault. Keep the discussion limited to risk factors and their relative potency. But that leads to another problem.
In some of the jurisdictions in which I practice plaintiff's counsel will successfully argue to the trial court that only evidence about about the actual cause of plaintiff's injury is admissible. In other words, unless my expert is prepared to say e.g. that "to a reasonable degree of medical probability plaintiff's breast cancer was caused by her not having children when she was young" testimony about "mere risks" is irrelevant and so inadmissible. The practical effect of such a ruling is that only junk science is admissible on the issue of the actual cause of plaintiff's cancer since my experts tend to be modest about the claims science can make regarding the cause of any individual's cancer. We're stuck then trying to prove a negative, showing we acted reasonably and preserving error.
In this age in which much that was certain (e.g. that we've conquered infectious diseases) is proving not to be so it's time I think for courts to recognize not only that the reasonableness of actions can fairly and effectively be judged according to the risks they conferred but also that causation is in many cases most precisely weighed when competing risks are allowed to be compared against one another.
Finally, and hopefully still on topic, for more evidence of the complexity of causation see "Does Pregnancy Provide Vaccine-Like Protection Against Rheumatoid Arthritis?" Why would pregnancy protect against auto-immune disorders and what's the connection with breast cancer? There are a variety of hypotheses offered but so far no one knows.
