After researching the science behind ultrasounds and their affect on tissue, it makes sense. I wish I had known before we went. The only reason we went is because Kaiser isn't going to do another one until our big 20-week one where they check everything out. Since we originally went at 7-weeks, the only "picture" we had was a big empty void with this little grain of rice! My wife wanted something that looked like a baby without waiting another 7 weeks.
If I knew last week what I know now, we probably wouldn't have done it.
We only paid for a 2D because she just wanted something more than the grain of rice picture. However, the lady was so excited that she wanted to see a 3D image, so she turned it on. Only for a few seconds, though. She said she was excited because she rarely gets to do them when they are this small and in the "alien" state. Most people come in after 20-weeks.