1996 July 24, Janet W. Hardy, “Re: Independence Day - The movie”, in bit.listserv.words-l[1] (Usenet):
I found out about 20 minutes into the workshop that at least six of the men in attendance had been born women. Not one of them had twigged my "transdar."
2000 July 26, Cheryl, “Re: everyone flame me, I deserve it.”, in soc.support.transgendered[2] (Usenet):
My hearing isn't that great, but my transdar immediately zoned in on him.
2013, Asia Friedman, Blind to Sameness: Sexpectations and the Social Construction of Male and Female Bodies, University of Chicago Press, →ISBN, page 59:
Other respondents offered similar descriptions of transdar as a keen understanding of the most important sex cues.