Who should I believe Sonographer or Doctor?

Dear Ms.Ultrasound

At 23 weeks I had a u/s scan done and was told by the sonographer that I'm having a girl. She appeared to be confident in her answer. At 35 weeks I had a u/s scan done to make sure baby wasn't breech inside my doctor's office and he said "It's a boy right?" I explained to him that I was told I'm having a girl and he said he might have read the sono wrong. Who do you think is more accurate?

Thank you