I have compared some distance calculations between geopy and PostGIS ST_Distance, and it seems that PostGIS ST_Distance uses the great circle distance rather than Vincenty.

>>> from geopy.distance import great_circle, vincenty
>>> p1=(32.083659,34.806480)
>>> p2=(32.0843373,34.8065365)
>>> vincenty_distance = vincenty(p1, p2).meters
>>> print vincenty_distance
75.4044140365
>>> great_circle_distance = great_circle(p1, p2).meters
>>> print great_circle_distance
75.6324224394

Does PostGIS have a Vincenty Distance calculation?