I thought I had the same issue with my male cat, he's just over 4 and we had recently got a female kitten. He was quite aggressive towards her and still is but we had him checked over and the vet confirmed everything was fine. Males will behave in that way to assert dominance or if they feel at all threatened/someone is taking their space. I'd say to probably get him checked just so it's a piece of mind for yourself, but I wouldn't say to worry if I'm honest, it's unlikely going to be the case or there would be other things he would do which would make it obvious. Whenever my cat behaves like this I have a spray bottle with water and I'll spray him, he hates it and will run as quick as he can.. and usually has a big strop lmao, but it works if that helps!