Megyn Kelly moved the political seismograph in an interview with former Chicago Mayor/Obama White House Chief of Staff/Ambassador to Japan/Possible 2028 Presidential candidate … when she asked him if a man could become a woman, and he said, “No.”
Megyn fired off a series of questions before hitting him with the biggie — Should men be allowed to play in women’s sports? Rahm said no. Should kids under 18 ever be put on puberty blockers? Rahm said only with parental consent. Should men be placed in women’s prisons? Rahm said no.

TMZ.com
After he said unequivocally men cannot become women — a position at odds with many if not most Democrats — Megyn exhaled with approval.
Rahm did add, “I’m not saying medically. I’m just saying it can’t happen.” He did not elaborate, but presumably he’s saying men can transition to a female body, but they’re still men.
What’s unclear is how he feels about the transgender community and transgender rights.