Several years ago, evidence of sex rules were specific to the hunt. In other words, in an either-sex hunt there was no requirement for evidence of sex; while in sex-specific hunts there was the requirement. Depending on the year, and the hunting season, the evidence-of-sex requirement did or did not apply - even in the same unit. This created confusion among hunters. In an effort to simplify the regulation and make it easier to comply with, the Idaho Fish and Game Commission changed the rule to standardize it's application for all big game hunting.
Fortunately, there are some very simple and uncomplicated ways of leaving evidence-of-sex. For females, leaving 1 teat attached to the carcass will suffice. For males, leaving a small section of the penil ligament (white cord entering the rectal canal) attached to 1 hind quarter is all that is needed.