Hi Nick,
Just remember when you see your Dad, just keep it real simple. Start by reminding your Dad, this IS NOT a choice. It's a well documented MEDICAL disorder. He had NOTHING to do with it, YOU had nothing to do with it and your MUM had nothing to do with it. It's purely and simply a genetic/hormone thing. Nothing more, nothing less. NOBODY can fix it. It's just like any other birth defect.
Simple. Just takes the pressure off everyone. No one is at fault, no one to blame. THIS IS NOT A CHOICE!!! end statement.
Hope it goes well for you. Let us know how you are coping.
Be safe, well and happy
Lotsa huggs
Catherine