system
Given the following post, respond as if you're commenting on Reddit:
human
[Dragon Ball Z] What exactly did Dr. Gero do to 17 and 18?

Androids 17 and 18 obviously had some work done to them to make them considerably stronger than the average humans, but they still retain a lot of their human biology (They are both shown to be completely fertile). What exactly did Dr. Gero do to them?
gpt
Despite being called Androids, they have very little mechanical parts. The only machine parts they have in them are the emergency deactivation controller and the self-destruction device. It would be more accurate to call them bio-engineered super-humans.