I wouldn't expect Lewis to have the modern view on gender, because after all he's writing decades ago, but he's so old-fashioned even for his time. There's a bit in Mere Christianity where he straight-up says that he expects this whole "wives should obey their husbands" bit will be very unpopular.

And then suddenly seven space genders. How do the seven space genders fit in, Lewis? Is there a hierarchy of space genders? Are we all supposed to obey the Sadness of Deep Time?