And that's the issue. One side says life begins at conception and backs that up with religious teachings. The other side says it is more of a gradual process and backs it up with medical research.

NASA has the following to say.

Livings tend to be complex and highly organized. They have the ability to take in energy from the environment and transform it for growth and reproduction. Organisms tend toward homeostasis: an equilibrium of parameters that define their internal environment. Living creatures respond, and their stimulation fosters a reaction-like motion, recoil, and in advanced forms, learning. Life is reproductive, as some kind of copying is needed for evolution to take hold through a population's mutation and natural selection. To grow and develop, living creatures need foremost to be consumers, since growth includes changing biomass, creating new individuals, and the shedding of waste.

Seems like a pretty strong case for "life begins at conception" to me.