I encountered this technical lack in all dating services. As most users don't set a value for each field of their profiles, it becomes difficult to set filters for encounters of profiles and browsing (how to set filter for these two features??).
For example a woman wouldn't set "have children" field.


Using filter criteria I have to set a value for a field or "any".
However it would be very useful to filter profiles that have some fields as "have children" positive by exclusion (and not inclusion).