This is a observational study to investigate the degree to which bone mineral density is impaired in boys with autism compared with typically developing controls.

Studies have shown that bone cortical thickness is decreased in children with autism and other developmental disabilities. However it is not known whether bone mineral density (BMD) of these children is lower; neither is it known whether there is any correlation between BMD and the child's diet. The overall goal of this study is to improve the long term health of children and adolescents with autism spectrum disorder; more specifically the investigators aim to develop a pilot study to investigate the degree to which BMD is impaired in boys with autism and to explore specific additional risk factors. In addition, the aim is to investigate the degree to which BMD is impaired in boys with Autism Spectrum Disorder (ASD) and to explore specific contributing risk factors including nutritional analysis.

Inclusion Criteria:

• Boys 8-17 years chronological age
• BMI between the 3rd and 97th percentiles
• Meets DSM-IV criteria for Autism Spectrum Disorder (ASD group)
• Scores <15 on the Social Communication Questionnaire (control group)

Exclusion Criteria:

• Use of medications directly affecting bone metabolism including estrogen/ progesterone preparations and glucocorticoids except local application of glucocorticoid
• Use of anticonvulsants which affect bone density including diphenylhydantoin, phenobarbital, topiramate carbamazepine and valproic acid and also use of lithium
• Children with diseases known to affect bone mineral density including Crohn's disease, celiac, thyroid and renal
• Children who will not tolerate lying still for 30 seconds

Adolescent boys, ages 8-17 years, recruited from a clinic population (ASD) or community advertisements (ASD and control) matched for age.