<human>: Can you condense the text into a few key points?

Some back story. My wife and I live close to our son and daughter-in-law. Her family is out of state. My wife watches their 2.5 year old son ant least once a week so the D-I-L can have some time to herself. Despite all the olive branches and efforts at trying to get close to her it seems she just does not like us. Today my wife watched the grandson while they went to the doctors. When they got back they told her that they had already called her parents (and other relatives) out of state and told them sex of the baby due in December. They didn't tell my wife, and only later said they wanted to reveal it at a party where everyone else will find out the sex. 

Am I wrong to be pissed at both of them for treating us this way?
<bot>: Son & Daughter in law let her parent know sex of baby and won't tell us. I'm pissed about it.