I know that "XX male" syndrome occurs through various means, including the addition of an SRY gene in one of the X chromosomes. The developmental and health outcomes of such individuals can be problematic. But what about a person with an X chromosome with an SRY addition, along with a Y chromosome?
It seems that it would be similar to XYY syndrome, but without the over-expression of anything but the SRY gene. Would it even be obvious, from a visual point of view or fertility point of view, that a person has the extra SRY gene?
I know that rodents aren't humans, but it does appear that there are species that have naturally acquired multiple copies of the SRY gene.