Be aware

I generalize. If you don’t like Man Utd, you’re a loser. And so with kids.
You cannot love all the same. Not for wanting or trying, but just because the human in you will tend towards one. The preference may keep changing with time. As you age, you will achieve an average median that will ensure, hopefully, your choice does not wreck the life of the lesser loved. But, I think, if you are aware of this, you may in fact work harder to love the one you love less. Makes sense? It’s not supposed to. It’s called parenting.