Yes, well, the argument would be that those children aren't human beings therefore "destroying" them is No Big Deal. Might as well punish their creators, too, by death.
I wonder what those people think of diabetics using insulin made by bacteria? What about organ transplants, both human-to-human and animal-to-human? What about blood transfusions?
Aww, heck, anyone who's had anything done to them by a doctor is a "monster." Right? 'Cause afterwards, they aren't as God made them...
Apples and oranges. You're referring to altering something that already exists. This is the creation of something that wasn't there out of something in the back of Fred Sanford's truck.
Engineering sperm from a female is counter to everything in Nature.