RameNoodle said:
Now, now, let's not get our personal beliefs involved here. (Although I agree...) I think that it's because the protestant religion "evolved" out of Catholicism and Catholicism says life begins at conception.
Just a side note, though, Judeaism says that life does not begin at conception, rather it begins at birth. God, I'm never going to a synagogue again.
By definition, life starts at fertilization. Whether or not it is human is a whole other matter.
A zygote does the following
Organization - Living things are comprised of one or more cells, which are the basic units of life.
Metabolism - Metabolism produces energy by converting nonliving material into cellular components (synthesis) and decomposing organic matter (catalysis). Living things require energy to maintain internal organization (homeostasis) and to produce the other phenomena associated with life.
Growth - Growth results from a higher rate of synthesis than catalysis. A growing organism increases in size in all of its parts, rather than simply accumulating matter.
Adaptation - Adaptation is the accommodation of a living organism to its environment. It is fundamental to the process of evolution and is determined by the individual's heredity.
Response to stimuli - A response can take many forms, from the contraction of a unicellular organism when touched to complex reactions involving all the senses of higher animals. Plants also respond to stimuli, but usually in ways very different from animals. A response is often expressed by motion: the leaves of a plant turning toward the sun or an animal chasing its prey.
Reproduction - The division of one cell to form two new cells is reproduction. Usually the term is applied to the production of a new individual (either asexually, from a single parent organism, or sexually, from two differing parent organisms), although strictly speaking it also describes the production of new cells in the process of growth.