That does not mean that the future human being is conscience of what is going on. This question must be about abortion. This must be some attempt to shame people into not having an abortion. If people are going to use the argument that life begins at contraception, then they have a lot of answering to do. People kill all kinds of bacteria in their body everyday by their own bad habits. Bacteria that is part of people and helpful. No one gets upset about that.
Human life does begin at conception, but consciousness may not necessarily begin there. An embryo is not fully formed, but it is in the process of becoming a human, so thus it is only natural to state that life begins at conception. Arguing about it otherwise is simply a matter of semantics, and that doesn't necessarily mean the abortion or stem cell arguments are invalid.
While you may not have a brain or be able to think at conception overall your life begins at that point, eventually you will grow and develop a brain and body but science believes that even though you are not aware of it you are alive at the point of conception.
I think that if we were to go by the beliefs of science, then life should technically being at conception. Life is defined by science in various ways. In science, something like a plant is alive regardless of the fact that is does not experience something like the ability to comprehend.
Some people argue that it is 'just' a bundle of cells. But where is the defining line?
Some say consciousness (an interesting point, I think, as it implies being aware of pain and pleasure) some say heart beating, some say when it is viable on its own (hard sell, as this would logically imply that people on life support are not actually alive).
The only definitive point is when an egg is fertilized.
But people in this debate (not just on this opinion post) have a lot of odd definitions of what they, personally, consider 'life'.
There are a lot of arguments that will say that a heart beat alone dictates life. If that was the case then many pro life believers should be much more sensitive to animals and other beings. The truth of the matter is that we need more than a heart beat to be alive, we need to be a functioning organism that can self regulate.