Here’s an ethical issue and Jewish source response:

Case

A doctor is very close to finding the cure for all types of cancer.  However, experiments on non-human animals have proven ineffective.  The only way to try out and perfect his new serum is to experiment on healthy human beings.  Until the serum works at 100% rate, about 55 people will be needed to suffer the pain of the imperfect serum and then die.

Is it ever proper to knowingly and willingly kill a few individuals in order to find a cure for a disease and save the lives of millions of people?

Answer

[a] The Mishna, the earliest Rabbinic law book, says: “Whoever saves one life, it is as if he has saved the entire world” (Sanhedrin 4:5).  This sets up a response to someone who might be thinking about using homeless people or prisoners for cancer experiments.  Jewish values say that all lives are equal.

[b] Judaism believes that it is not up to people to decide the value of any life over another.  We cannot say that the life of a homeless person or that of a prisoner has less value than anyone else’s life.  The Talmud (Sanhedrin 74a) expresses this concept with the question: “Who says that your blood is redder than his blood?” This comes in response to the case of someone telling a person to kill or be killed himself.  You may not kill to save your own ‘red blood,’ because it is worth no more than your fellows.  Each person is deemed as an equal to any other, and it is for this reason that only one human being was originally created (Sanhedrin 37a) – so that no one could say that “my ancestors are better than yours.” Only God is the true judge.

[c] Regarding the questions of killing a few in order to save the lives of many, we know that any act of murder is one of the most serious offenses in the Torah (Exodus 20:13):  “You shall not murder.”  It is forbidden to knowingly kill one person to save the life of thousands or even millions.

[d] In addition, Judaism does NOT believe that the ends justify the means.  Thus, if one can do a great mitzvah, but only by committing a sin in the process, a Jew is not permitted to do such a mitzvah.  It is for this reason, for example, that a stolen lulav is not usable for the mitzvah of shaking the four spices on Sukkot (Sukkah 30a).  Maimonides (Hilchot Issurei Mizbayach 8:9) says that God detests any gift which comes about through the commission of sin.  Based on these ideas, it would be clearly forbidden to kill even one person, even a sinner, in order to develop a cure and save many more lives.  

Joel Grishaver, “You Be the Judge 2”, pgs. 93-94

Used with permission from Joel Grishaver