Oh dear, I sincerely hope talking to the friend about the matter goes well and that her positive intentions can be harnessed to better ends in future. While good intentions are laudable, intent does not magically negate effect.

Personally, I'd be particularly perturbed by the lack of consent and the way the 'experiment' could have reinforced the entitled notion it's acceptable to treat the existence of trans people as a toy to play with for those participating in it. It would be unfortunate if the cis women she spoke to were given the impression it's acceptable to collectively talk about or guess the status of other trans people given the potential for compromising safety or creating other major issues for those targeted.

Hi Grace, I think the fact she told you meant she thought it was a "good" thing. Although I cannot understand how she came to that conclusion!

You've known her for 30 years and she's more "odd" than bad intentioned, so I would agree with having a quiet word with her about her strange "experiment". I think that at times even those with good intentions get a bit caught in the "OMG, I know a trans* person" headlights and do or say some weird stuff.

I've no doubt you'll put her straight!

Quirky friend.
Sounds like she meant well, probably intention to reassure you about how well you pass.
And she probably was oblivious about the possibility you might be offended.

Talk to her, and be gentle.  I have a friend who's like a cocker spaniel.  Very loyal, dumb as when it comes to personal tact, but always means well.  I just face palm every time he does something stupid.

Yeah, I wouldn't burn bridges with an ally for anything less than a truly egregious breach.

It sounds like she's a little ditzy and just didn't know any better, since it wasn't malicious you should just have a talk with her.

my friend did something similar
she showed pics of me to her friends and asked if they see anything wierd
they said they see nothing wierd just a bunch of girls...

so i was happy
she did it to reassure  me that  i look female

Grace, I think it would have been appropriate if your friend J had mentioned her plan to you as to whether you would be comfortable with this & if you felt this would out you and not want J to do this, that she should abide by your decision.

Perhaps that is a gentle way to broach the subject with J. Seeing as you have been friends for 30 years you must know each other well enough that your relationship will continue. Best wishes.

Just my take on the issue. You are progressing into a pretty lady.
Hugs
Jamie

My wife (post-op and full time some 30+ years) had experienced even more 'Bizarre' experiment from lovers and other T friends. Confused and or conflicted lovers that had to get approval from a trusted confidant, or another T that wanted to use her as 'justification'.

Essentially you tell the third party I am going to introduce you to a T. Now tell me whether or not she is a perfectly normal woman and you had no idea. Talk about a destined to fail test!

Your friend ran a far better version, using a cop show photo array to try to pick out the perp.

You should know by now the conflict cis people experience when confronting gender. Add religion into the mix and you got bigger mess to deal with. Sure it hurts to know she needed validation of what was likely her feelings of how well you present. She also probably felt she could not trust her opinion since she is 'too close' to the situation, much like my wife's friends in the past. You also forced her to confront her religious beliefs on 'deviants', such as yourself. Obviously you aren't quit up to the standards of "Evil" that she expected.

Oh - just make sure you put all the "Trans Agenda" training manuals away before she visits you. 

Grace,  am sorry this happened to you.

I am glad you will be discussing it with her. She probable does not understand she treated you as a picture and not a person with feelings. Being judged whether passing or not or being trans or not is harsh.  Being trans the subject can have major issues associated with it due to hyper sensitivity on the subject.