I hadn't thought about same-sex couples but, of course, you are using the gender switch to detect Bride or Groom so it cannot work. But I am also surprised that there was no error or problem because of the missing ">" while adding it in does create a problem - I must have miscounted somehow in my transcription.
To have a common sentence for the same-sex Principals of a Marriage fact shared with their respective parents or other related witnesses is probably going to need an enhancement to the sentence template language. Something like a modifier that returns or tests for "husband" and "wife" (using database terminology) on the two Principals of a "family" fact. For example,
-- return True or False:
Then with the enhancement of the :husband modifier, this sentence template should work:
[Person] married [Spouse]<?[Spouse:husband]<?[Parent_of_groom]<%[Spouse], son of|, daughter of> [Parent_of_groom]>|<?[Parent_of_bride]<%[Spouse], son of|, daughter of> [Parent_of_bride]>< [Date]>< [PlaceDetails]>< [Place]>.
Note that I have replaced Father_of_groom and Mother_of_groom with Parent_of_groom and likewise for the bride. Parent_of_bride will list all persons with that role.
I'm not sure there is a need for both :husband and :wife modifiers. Only one is needed to test - true for :husband would be false for :wife and vice versa so either :husband or :wife is sufficient and maybe the test should be for :Principal1 or :Principal2 to reduce ambiguity. There might be a trap in using this modifier for a non-family fact - should it return Null and, if so, ignored.
Edited by TomH, 19 January 2017 - 01:38 PM.