My boy is neutered. He showed signs of reactivity before that though. I'm not entirely sure but it did seem to get worse after he was neutered. But that could also be I had no idea what I was doing training wise.
My mom's rescue dog is very scared of things blowing in the wind and is nervous around men she doesn't know. I am correcting her when she acts up around small dogs.
He's also very reactive towards other dogs. But thankfully I've finally found a training style that has helped him. On our last walk we saw 2 dogs and not a single reaction! So proud of both of us.
I wish my dog was more friendly and outgoing. It takes him a bit to warm up to people. And he loves women more than men. He still doesn't care much for my dad after 5 years lol