Just a few related questions on testing....

My brother has CAH and I don’t.  I’m probably a carrier and am about to start having children.  My wife doesn’t have any family history with CAH. 

To get tested I’m told is about $600 which apparently my Oxford Health doesn’t cover on the paternal side.  I am told that it also depends on which lab does the testing in relation to whether its covered.  Has anyone had the testing and found a better way? Why wouldn’t an insurance company cover this??  I hate to make this into a money issue but it is a good amount....we will get tested one way or another but I’m just trying to make sure I know all the options on costs/insurance.  Many thanks in advance for any help!