Just because someone was able to procreate doesn't mean they will be a good teacher either.
but being a homeschooler is not about "being a good teacher" in the way of a classroom teacher... it's more about being a parent who knows his child, knows/learns what his child needs, knows/learns/figures out how his child best receives whatever is going to meet that need... and this takes some trial and error; picking and choosing; give and take...
it's not like successful homeschoolers would automatically be successful classroom teachers... and that is not what is needed to homeschool...