The Doctor on the Enterprise, Dr Phlox is a native of Denobula Triaxa.
Denobulans are typically polyamorous, where a man typically has three wives, who each has three husbands. This creates extremely large extended families.
Denobulan families are large and complex; the family of Phlox, a typical member of the culture, had 720 members, with 42 romantic partnerships. An individual usually aims to acquire three spouses, each of whom will themselves have three other mates. Other combinations are not unknown, but tend to be frowned upon by mainstream Denobulan society.
Set early in the 22nd century, 150 years before James T. Kirk helmed the famous starship, this fifth installment of the "Star Trek" franchise explores the history of the intergalactic upheaval that eventually leads to the formation of the Federation.