CLAIM: Moses explains, “If two men are fighting and the wife of one of them comes to rescue her husband from his assailant, and she reaches out and seizes him by his private parts, 12 you shall cut off her hand. Show her no pity” (Deut. 25:11-12). What do we do with this bizarre law?
RESPONSE: This is probably referring to justice “on the spot,” rather than later. It might be similar to a SWAT sniper shooting someone with a hostage. This might be the prevention of harm, rather than the retribution of harm. The text never says that the woman crushes the man’s genitals—only that she grabs them. This act was so egregious (i.e. crushing a man’s testicles) that the law told them to cut her hand off before she could cause the man harm. If the man had his testicles crushed, this would not only be exceedingly painful (!!), but he would lose a stake in the community of Israel (Deut. 23:1) and his offspring. So, this was treated very seriously.
Copan argues that the Hebrew in this verse is actually referring to publicly shaving the woman’s pubic hair! That is, the woman was to be publicly humiliated for her actions. He makes a linguistic argument for this, but I don’t find this much better than the plain sense reading. It seems nearly just as bad (and ultimately more bizarre!). However, Copan also points out that this law was still ahead of the ANE at the time. He writes, “In fact, Middle Assyrian laws (around 1100 BC) present a similar scenario (in the case of injury to the man), though with far more drastic consequences. If a woman in a quarrel injured a man’s testicle, her finger was cut off. If the other testicle was injured, both of her eyes were gouged out.”
 See Copan, Paul. Is God a Moral Monster?: Making Sense of the Old Testament God. Grand Rapids, MI: Baker, 2011. 121-122.