I think you may be reading a different article. I just read it and don't see anything about them engineering the female mice to produce sperm and a penis as you

I think you may be reading a different article. I just read it and don't see anything about them engineering the female mice to produce sperm and a penis as you note. Rather it says, "It was easier with double mums. The researchers took an egg from one mouse and a special type of cell - a haploid embryonic stem cell - from another. Both contained only half the required genetic instructions or DNA, but just bringing them together wasn't enough. The researchers had to use a technology called gene editing to delete three sets of genetic instructions to make them compatible." Also it "did work" with the male mice it notes, however they died a few days later, vs the females who had healthy babies that went on to have their own babies.