I don't have anything to back this up, but there's a weird quirk in "viking" law (from one place at one time). Sex between men was strongly, brutally condemned. But only the "passive" partner was considered to have transgressed. The "active" partner was not believed to have done anything unlawful or shameful. I've long wondered if this hints at a gender category of people like modern trans women. If having sex as the "active" man was not considered taboo, but being the "passive" man was violently condemned, could that mean there was a category of people who were considered to be distinct from men, but similar in some respects, and having sex with these people was not considered having sex with men, hence the need for legal specificity?

Idk, gender and northern europe is fairly weird. At certain times and places we have evidence of extreme violence against men who transgressed gender norms, but we also have stories where Odin transgresses gender norms in the most taboo ways possible. Loki is famous for using his shapeshifting abilities to change gender and at various times performs the biological role of both male and female parent, both siring children and giving birth to children. Thor gets in to some gender bending adventures as well. Freyja and the valkyries have strong associations with stereotypically masculine activities like war and hunting. Notably, while Odin's hall of Valhalla is more famous, he actually splits the valorous dead fifty/fifty with Freyja. Freyja hosts half of the valorous dead in her hall called Folkvangr. I don't know exactly what to make of that, but I think it's not entirely unreasonable to suggest that Freyja was considered a war-god co-equal with Odin in prestige and honor.