Rhetorical conditionals (Quirk et al 1985: 1094)*:
If they're Irish, I'm the Pope.
If she doesn't get first prize, she's no daughter of yours.
Since they focus on something opposite to the truth, can such conditionals be turned into the subjunctive:
If they were Irish, I would be the Pope.
If she were not to get first prize, she would be no daughter of yours.
* Quirk et al. 1985. A Comprehensive Grammar of the English Language. London and New York: Longman.