A sperm is not fully and genetically human. It will not develop into a human of its own accord in the womb (except in Woody Allen movies).
The point is, when is it a human being???
I believe the fine line between what is a human life and what is not a human life is the developmental stage where it goes from a zygote (embryo) into a fetus (an unborn human).
You can freeze an embryo for decades (probably longer), you can implant it into another human that was not the mother. You cannot do that with a fetus.
A fetus is a living person, and an embryo is not.