That's a shame - clearly having sensitivity training doesn't necessarily mean one will be sensitive, but it's especially troubling in a family setting (though probably pretty common).

When I spoke with my sister several weeks ago she just flat-out rejected the idea that I'm trans (including saying "you don't look like a girl").  I haven't communicated with her since then for the same reason you mentioned, I'm not sure how to approach/re-approach the situation (fortunately I'm much closer to friends, who are supportive, than family)

"She called me by my birth name over text (because she doesn't like to hear the truth when she asks my opinion, apparently). I corrected her, and her response was, "well it's not official yet!""
While I'm sure this probably stung, maybe it's not as bad as it seems.  I questioned my brother's actions a few years ago, but members helped me pretty much see that he most likely really didn't mean anything.  I think the biggest problem was that I called him on something, and he became defensive.  That could be where your sister's comment, "well it's not official yet," came from.  That doesn't excuse it, but it might explain it.

"This is the most shocking because she has actually had diversity and sensitivity training with her job, which included an LGBTQ section and focused on transgender discrimination."
Now that I've somewhat defended her... I will say this much about employer-mandated sensativity training:  such training is not going to change someone who doesn't want to be changed.  And really, I'm pretty sure that sending employees to sensativity training is just a company's way of covering it's rear, to make sure their employees treat "anyone different" respectfully.  It's to cut down on grievances and possible lawsuits.  Sensativity training normally is not elective.  Too often, many people don't like being forced to go to them.   And most of them see it as a challenge to their [sorry] character.

Hopefully she'll come around.
-Michael

Dear Brigsby,

What you describe is not only transphobic insensitivity, but also adult sibling bullying, which is more common than you may think.

Have three brothers and a half brother that bullied me as a child and as an adult.  Children do not automatically outgrow sibling rivalry.

The good news it, often, it DOES get better.  Please give it time and do everything you can to not let her have the satisfaction of getting under your skin.  Forgive me, but play deaf, dumb and blind.  In one ear and out the other.  My brothers would humiliate me in public (even as adults!) and they only made a fool of themselves.

You have "brothers" and "sisters" here at TGGuide who accept you for who you are!

Yours truly,

Monica