Well, I can tell you how it happened for us. My wife loved Yorkies and I had no interest in them at all. I had Toy, a Wolf/German Shepherd mix, and didn't want another dog. So what does she do? She gets 'me' a Yorkie for my birthday!! I'm like, "what is this?", but it took just a few minutes for him to become my Dog-son.
So, what's the worst she could do if you brought 'her' home a little girl? Wait, don't answer that.
Bet it would only take a few minutes for her objections to fly out the window. Well, at least that's the way it worked out with me
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Seriously, best of luck 'convincing' (wink wink) her and I look forward to pics of your new little angel.