Don't want to sound dumb but can ultrasounds be wrong? He's a boy right?

Emily
I've been freaking myself out reading stories about ultrasounds being wrong about baby's sex. Not that I'd love my baby any less if it was a girl but I've boughten boy stuff and everything. I'm like 97% sure we aren't wrong but everyone else sees boy right? It's not like the cord or anything? I know I probably sound silly