We have always found that the temperament of the individual puppy plays a bigger role in personality than gender but here are some generalizations we have found over the years.

Male Irish Jacks tend to be a bit bigger and stockier than their female counterparts. The males often tend to be more docile and easy going.  A neutered male will not generally mark his territory in the house or yard.

The females  have a more petite look and are usually more sensitive and can become more attached to their specific owner.