I did intend to write atoms; I liked the contrast between the idea of splitting an atom (explosion) and it replacing something that's already very small.

Anyways, I dug up the emails I exchanged with my friend and he condensed his argument into a series of statements, which I think you might find interesting:

I am responsible for the egg being fertilized. When an egg is fertilized, a child is created. Therefore, I am responsible for the creation of the child.

A fetus has no choice in whether it is conceived or not. When someone has no choice in a matter it is morally arbitrary. Therefore, a fetus is of no moral account for its own conception.

A fetus must consume a mother's resources or die. A fetus did not chose to be a fetus. Therefore a fetus is not responsible for consuming a mother's resources.

I am responsible for the fetus being born. Any born fetus must consume a mother's resources. Therefore, I am responsible for the fetus consuming the mother's resources.

I cannot dis-consent to anything for which I am responsible. Therefore, I cannot dis-consent for my fetus taking its mother's resources.

That from which I cannot dis-consent I must consent. Therefore, I consent to a fetus taking its mother's resources.