Fertility in cryptorchidism: an experimental model.

Because the long-term efficacy of treatment for cryptorchidism is difficult to evaluate in humans, we developed an animal model to study the effects of cryptorchidism on fertility. Sprague-Dawley rats were treated within the first few days of life to create either mechanical or endocrinological cryptorchidism. The ability to father offspring was used as a measure of fertility. Significant differences in fertility between rats with bilateral cryptorchidism and controls were observed, regardless of whether the cause was mechanical or endocrinological. Rats with unilateral cryptorchidism were significantly less fertile than those that underwent unilateral orchiectomy. Further development of this model will permit prospective evaluation of different treatment modalities in cryptorchidism.