what is the reasoning behind health insurance companies?

what is the reasoning behind health insurance companies not wanting to cover the cost of birth control pills .but would pay for pregnancy Dr appointments, delivery, hospital stay and health care for a baby until 21 it does not make sense to me and I'm sure others agree with me
--------------------
I just answered a similar question to this one. So, I will just basically copy+paste the answer I just gave. I hope it helps you. I have worked in the health insurance industry for over 20 years. You will find this with many group insurance plans. Group health plans are basically written by the group (or corporation) and implemented by the insurance company. This means that the company you work for can make Viagra or birth control a benefit or not. The exception to this rule is if you live in a state that mandates this drug (or medical service) has to be a benefit. This mandate will override an insurance company policy. There are some corporations that play the sexist game of allowing Viagra but disallowing birth control pills. Many people don't know it but Erectile Dysfunction medication is covered by some Medicare Advantage plans. Meaning grandpa Eddie can still get his groove on. I will add that most individual (non-group) health insurance plans do not cover birth control.
Source