You may have not been told the term "Anorchidism" for this condition, you may have been told of this by another term or name.
Congenital absence of testes
TRS (testicular regression syndrome)
Vanishing testes syndrome (VTS)
Anorchia or Anorchic
In all of these terms the conditions are the same, so that if you have been told one of the above names that either affects you, or your son.
ASG may be the group to contact for help and support.