The Tumbler Ridge shooter was a trans female. How rare is that?

RCMP on Wednesday identified the perpetrator of the mass shooting in Tumbler Ridge, B.C., as 18-year-old Jesse Van Rootselaar, a transgender female. Dwayne McDonald, deputy commissioner of the RCMP in British Columbia, said that Van Rootselaar was born a biological male and began to transition to a female about six years ago.

McDonald added that Van Rootselaar "identified as female both socially and publicly."

He also confirmed that a total of nine people died in the shooting, including Van Rootselaar. One victim who was reported to have died en route to hospital is alive and in serious condition. The victims included one female educator, three female students and two male students. In addition, Van Rootselaar's mother and stepbrother were found dead in their home nearby...