the abh don't seem to have any real social stigma though, going by III they are traveling together and apparently share the same quarters.
lafiel's 'mother' didn't seem to have any rank, and her and lafiel's father were taking a vacation together. been a while since i've seen the OVA, but they may have even said honeymoon, despite not having marriage lovers taking long sabbaticals together doesn't seem uncommon
i guess they are building up the relationship to the point where they ask for the other's genes. hopefully they won't be corny and do it at the same time