Well, it is typical for animals to possess their genitals in between their hind legs because, while they are quadrupedal, this protects their reproductive capabilities from physical harm.
The yautja are clearly bipedal, which in turn means that they must have evolved to stand upright in order to spot potential predators (NOT yautja) before they were attacked. If my theories are correct, said carnivorous predators were the xenomorphs.
Following typical biological information, it is safe to assume that their genitals have remained in the same location. This also explains why they would clothe themselves in that region and wear protective armor there.
So, in short, yes. They do have genitals.
And thus I clothe my naked villainy
With old odd ends stolen forth from holy writ
And seem a saint when most I play the devil.