16 week ultra sound

So we had our 16 week ultrasound the other day. The baby measured at 15 weeks and six days, everything looked healthy. What confused me was the gender reading. The tech said it looks like a boy but it's usually too early to tell and she couldn't be sure. Everything I've looked up says it's a boy, but why would the tech be unsure? Do little boys and girls at this age look the same. I go in for an anatomy scan at 22 weeks but I am impatient and want to know lol. Any clarification would be helpful, the Internet searches didn't help much so I'm hoping experienced mommas out there have an idea.