Same with testes being converted to ovaries which has existed for quite some time but as an experimental method. Only one TIM in the UK managed to go through it.
I was intrigued, and I try not to be too sceptical, so I've just spent some time reading interesting papers courtesy of PubMed. The nearest I can find is a 2009 discussion of suppression of FOXL2 gene expression to convert ovarian tissue to testicular type cells:
https://www.cell.com/cell/fulltext/S0092-8674(09)01433-0?cc=y
I can't find any update that says it's successfully been attempted in humans, or a testicular to ovarian conversion. Maybe there is, though; I recognise Lovell Badge's name so I assume this isn't total, erm, bollocks.