„The atrophy [of the thymus] is due to the increased circulating level of sex hormones, and chemical or physical castration of an adult results in the thymus in

„The atrophy [of the thymus] is due to the increased circulating level of sex hormones, and chemical or physical castration of an adult results in the thymus increasing in size and activity.“ ( https://en.wikipedia.org/wiki/Thymus https://en.wikipedia.org/wiki/Thymus ) So the study might simply have show, that by decreasing sex hormones the thymus is stimulated to grow. But the side effects of no sex hormones might be much greater than the advantages of a younger immune system.