Genetic Testing

I'm a little nervous. Dr asked if I wanted to come in for a 10 week genetic testing that also can tell you the gender of the baby. My husband really wants to do it so we set the appointment. However, I have heard different things about it. First I heard that all they do is an ultrasound with some blood work from your vein. Second thing I heard is they take amniotic fluid from your belly which can cause a miscarriage. I left a voicemail for the dr to call me back but I want to hear from your experiences. Has anyone had this and how was the testing done? Thanks!