Autism spectrum disorders affect more than two million Americans and rates of diagnosis have increased by 10-to-17-percent over recent years.  Although autism is a complicated and varied condition, there are some tests that can help diagnose children.

For example, scientists can look to see which side of an adult's face babies focus on. Human brains are wired to look at the right side. Studies have shown adults with autism don't favor a side.

Speech recognition technology can look for patterns in the child's voice, such as abnormal pitch quality and rhythm, that may also indicate autism. If one of your children already has the condition, their sibling can have a seven-fold increased risk of developing it too, according to a 2013 Danish study.

Another recent study found girls may be underrepresented as autistic simply because they're being misdiagnosed. The study said young girls may simply have different symptoms than boys, and these can often be overlooked by medical professionals.

Experts say Autism begins during early brain development, but symptoms and signs usually cannot be seen until the child is two or three. About 1 and 88 children in the U.S. will develop some form of autism and it is about five times more common in boys than girls.