My in-laws are very religious and we are not. Despite this, we have let DS attend church and religious services with them because it's import to DH and I that our son be exposed to a variety of ideas. We try to be accepting, and if nothing else respectful, of their beliefs.
We chose the name for DD as a family and have gotten negative feedback on it from our moms. But, my mil decided to make it way worse. We have chosen the name Caitlyn because we had chosen Kathryn for another pregnancy. We loved the name but felt we couldn't reuse it. (This is our 5th and we only have one child.) She called DH to tell him it was "disgusting" that we would name her grandchild after Bruce Jenner and it made her sick to her stomach. She went on for a while and eventually DH just hung up on her. This is pretty out of character for him, but needless to say, he was upset. I don't know everything she said, but apparently there was a long rant against people who are transgendered and people who are gay. (Even though the two aren't related…)
My brother is openly gay and she has repeatedly told me that she likes my brother, but it's a shame he's going to hell. I can only imagine that she tied my brother into this. If she did, I don't want DH to tell me. I'm mad enough already.
I have so many problems with her views on people who are not heteronormative. I don't usually say anything because I don't feel it's my place. However, this was so out of line.
I don't know how to handle this with her. I'm sure I'll figure it out but seriously. Wtf is wrong with her???
Side note: I'm not interested in your thoughts on people who are transgendered or gay, religious or non-religious. Just needed to vent my frustrations with my mil.

Re: Need to rant
However, DH are not okay with her making these statements. It is not okay for our son, and soon our daughter, to be hateful toward anyone and I have concerns about her ability to filter herself around them.
Good luck.