son's odd fascinations

My son is 4 yrs. I am very concerned about his fascination with horses. He likes to line up any books he has with horses in it, then lay them on the floor and look at them all the time. When I ask him what he likes about horses, he says the tails.  A couple times I've noticed he got erections while looking at them. I don't want to make him feel embarrassed, or shameful. He is only 4. Is this something I should be worried about? Is this just a faze? Please Help.

[Kevin Kennedy, Ph.D.]

No, there is no reason to be worried. And there really is nothing to be done about it in any case. Just be sure he has exposure to normal play and activity situations for his age, including opportunities to play with other children his age.