The SLED Test is a conversation piece, originally developed by Stephen Schwartz in his book, Moral Question of Abortion, that uncovers a few ways to logically discuss the value of human life.
The acronym SLED stands for size, level of development, environment, and degree of dependency. From this thought process, we can share the reality that personhood is not defined by any of these four things.
Now, anyone who has talked with an abortion advocate knows that the dynamics of real conversation many times make it impossible to give a four-step argument like the SLED Test.