7 Year-Old Missing 6 Permanent Teeth...Could dentist be wrong?

Hello!  I have always taken my children to the dentist every six months since they were one.  My 7-year-old was referred to an orthodontist for a possible issue with her bite.  Her appointment was yesterday and they did a full mouth X-Ray.  The Orthodontist blurted out that she is missing 6 permanent teeth!!!  The missing teeth are one molar on each side (upper and lower) and her two front lateral incisors.  I am in complete shock!!!!  I have never even heard of this happening when another condition is not present.  My husband is a principal and I was a special education teacher so we would see this with some of the children who had other disabilities.  Our daughter is a beautiful, extremely intelligent little girl AND we have never had anyone in either of our families have this (at least in the last 3-4 generations).  Is there a possibility they just haven't developed yet?  Or could they just not appear on the X-ray for some reason?

I know this diagnosis is not life-threatening or anything and I am grateful for this.  But I am understandably soooooo upset about the harm this could do to her self-esteem in her teens.  I understand they can do many things with braces, flippers, and implants when she is 18...not a fun road for a kid.  I guess I'm just hopeful still that there may be a mistake or maybe they just haven't developed yet.  Please help if you can!!!  Thank you in advance!!!

[mammo]

Check out this website for more information on this.

http://cyberdentist.blogspot.com/2007/01/congenitally-missing-permanent-teeth.html