Women in Clinical Trials

Women in Clinical Trials
When new drugs or medical procedures are ready to be tested on human subjects, researchers find volunteers for clinical trials. However, far more men than women are used as subjects during these trials.
It was widely assumed for many years that women and men would respond to medication in the same way. Therefore, it did not seem to matter whether men or women were participating in clinical trials. Because of this, researchers mostly drew from pools of male volunteers because they were perceived to be more low-risk (and accordingly, less expensive to include in a trial) . Women who are pregnant, nursing, post-menopausal or even simply of childbearing age are considered too "risky" to participate in clinical trials. These parameters essentially eliminate all women. However, it is difficult to determine whether this decision to eliminate women was made out of beneficence or paternalism.
The main problem with this gender discrepancy is that men and women are physiologically different. Their bodies process medications and respond to treatments differently. The over-representation of men in clinical trials has impeded the progress of understanding how new medications will affect women.
Question: What is the main idea of the passage?

A) Men often respond more positively to the effects of medications than women do.
B) Scientists used to think that all humans-both male and female-responded the same way to any given drug.
C) Women should be included in more drug studies since their bodies can respond differently to medications.
D) Researchers use volunteers for clinical trials when they need to test a new drug or medical procedure on human subjects.