I wonder if Midianite women had a reputation for sexual prowess
You may not remember this, but when Moses fled Egypt to escape the criminal justice system he took refuge in Midian. While he was there he married a young Midianite woman named Zipporah, daughter of Jethro. Given Moses’ past relationship with Midian, it might surprise you to learn that when the Hebrew migration passed near Midian, Jehovah commanded Moses to wipe out the Midianites.
Apparently the Midianites were pretty weak sauce because Moses only sent 12,000 fighting men; 1,000 from each tribe. After the Hebrew heroes finished the long walk to Midian, they wasted no time in killing all the men. Then they took all the women and children captive, gathered up all the livestock and valuables, and burned every building in the country before returning to report to Moses.
When Moses received the war report he was furious. He said to the military leaders, “You didn’t kill the women? Are you crazy or just stupid? Don’t you realize that when Jehovah says he wants genocide, he actually wants genocide? Do you want Jehovah to kill us for not following orders?”
Moses immediately launched his plan of remediation. He had his people kill all the male Midianite children and all the women who failed the virginity check, and commanded that all the young virgins be immediately married to their captors.
This was a good start, but it wasn’t quite enough for the Lord. Jehovah spoke to Moses again with some additional steps: “Divide all the loot from Midian into two equal parts, divide one part among those who went to Midian to fight, and the other part among those who stayed behind. Then from the fighting men’s half, take one in every 500 young virgins and animals to the temple, along with one in 50 animals and virgins from the half for those who didn’t fight. Then sacrifice all those virgins and animals as a formal apology for not committing genocide properly and give all the looted money to the priest.
Ref: Numbers 31