Hello,
We are fitting twin ACE models (and hopefully later twin ACE Cholesky models) using Finnish register data with no information on twin's zygosity, relying on same/different sex identification approach. This seems to be pretty straightforward with OpenMX but we have not found a way to do it with umxACE. Presumably, this is something that could be achieved with umxModify by changing paths but we were not able figure out how and were not able to find any examples either. Any suggestions how to proceed?
Best, Jani