>>2455414The ethical problem is that you're creating a presumably conscious being solely for your own pleasure. The relationship is one of parent to child, not of lovers. How does one weed out the people who just want to raise a catgirl to adulthood as best they can, providing them with all the opportunities they can be afforded and ensuring them a happy life, from the perverts who want to molest their catgirl. That's an essential filter to maintain.
If you want a relationship with a catgirl you shouldn't raise or adopt one, you should meet one out in the world like you would a typical person. Then, of course, the question is raised of how to do that without society having already struck down the possibility of catgirls in the wild existing.