This is via Butch Stroll, and cross posted with his comment board.
Here is the report from a news agency called AFP on an apparant woman in Burma who apparantly grew a penis at age 21, after praying to be reincarnated as a male.
It looks like a case of 5-Alpha-Reductase Deficiency, a recessive genetic condition that leads to ambigious genitalia at birth that can sometimes develop into full male genitals at puberty. Officially such people are male pseudohermaphrodites.
There has been a lot of anthropological work on a villiage in the Dominican Republic where this condition is sufficiently common that it has been accepted in the the folk conception of gender under the name "guevedoce": balls at twelve. Children born with ambigious genitalia are considered female until puberty's rush of testosterone allows them to complete genital development, at which point they are reclassified as male.
It is a little odd that her penis didn't appear until 21. Perhaps she was exposed to something in the environment that triggered the release of testosterone.