When does science say life begins ?

Question

I read where people who are against abortion say "Religion didn't decide when life began, science did ." . The point was that science determined that life begins when a fetus' heart starts beating, etc, but that was years ago, and I'm vague on the details . I know a fetus' heart doesn't start beating until a long time after conception . Apparently, biologists are looking for a series of bodily functions when they're trying to define life in a fetus . What kind of bodily functions are they looking for ? When DOES science say life begins ?

Answer 1

Science doesn't actually have a consensus on when "life" begins - at least not in the way intended in this question.

In the most fundamental sense, science says life began ~4 billion years ago, and has existed continuously ever since. That is, at no point in the process of the development of any organism does something non-living become living. Everything now-living cell came directly from some other living cell. All the way back to the first cell. The sperm and the egg are just exactly as alive as the testes and ovaries they came from, and just exactly as alive as the zygote they combine to form.

A human being on the other hand could be said to come into existance, from the point of view of different branches of science, anywhere from there to birth. But anything earlier than the development of the brain is essentially pointless, since there can be no sentience without it.

Ultimately, the definition of a human being is a matter of ethics and rights, and therefore of law, not of biology. And the law considers the status to move along a continuum from "not yet a person" to "fully a person", balancing the rights of that biological entity against those of the mother. And most literally, a person exists when they are born.

Answer 2

a fetus meets all the scientific requirements for life at conception

Answer 3

When you are a human embryo..... that's why a lot of people are afraid to do stemcell research, because you get stemcells from the human embryo, and by attempting to get the cells, you could kill the embryo.

Answer 4

3.6 Billion years ago, with Archaebacteria