...Yes?

Pretty sure that'd be manslaughter unless there's proof of murderous intention.

Depends on whether or not it was immediately obvious to you that the man you punched had brittle bone disease

Depends on whether or not it was immediately obvious to you that the man you punched had brittle bone disease

I actually do know the law on this. The apparent condition of the victim is irrelevant if you meant harm. In other words you take them as you get them. If the punch was in a fight where you defended yourself or even by accident, it isn't murder. If you up and popped a guy and his head caved, its second degree murder.

But, is this morally right? Should you be held to the level of scrutiny that anyone you punch could have this rare disease?

That's murder. Maybe don't go around starting fights.

Manslaughter, same way if you one-punched someone and they fell over and cracked their head on the pavement.