There are only 4 main differences between a born human being and an unborn baby (SLED):
Size: Does how big you are determine who you are?
Level of development: Are 21 year olds more human than 10 year olds because they are stronger and smarter?
Environment: Does being inside a house make you more or less a person than being outside?
Degree of development: Does dependence on another determine who you are? Is someone on kidney dialysis or with Alzheimer's less of a person?
~ Taken from Why Pro-Life? by Randy Alcorn