Purely from a health perspective, a sterilization, both male and female, is grossly unnatural. It cuts off the normal flow of "chi" - and then you do have problems!

Don't jump the gun. As someone else suggested here, just recover your own health, and you will be surprised how things just fall into place for you. "When God closes a door, he opens a window, etc. etc"

Animals feel pain & suffering just as we do, and they value their lives as much as we value ours.