From UFStarfleet LCARS
The Deltans are a humanoid species from the planet Delta IV in the Delta star system, Alpha Quadrant. They are naturally a very gregarious fun loving species, as well as having a highly developed sense of humor. Deltans are a highly sexual race and sexual innuendo permeates every facet of life on Delta IV.
Because of this heightened sexuality and the resulting possible insanity in other species from intercourse with Deltans, all Deltans who serve in Starfleet are required to take the Oath of Celibacy upon entering Starfleet Academy. Due to the nature of Deltans, they are also required to have regular Medical Checkups to ensure the pheromones are not impeding their fellow crew or their own duties.
If the Deltan people may be said to be a hypersexual race, it is because their entire species was threatened by inbreeding long ago. Many microcultures existed on Delta IV in the distant past and the extensive planetary chains of islands though they never quite developed xenophobia of one another. To prevent inbreeding, the Deltans developed an extremely open culture, lending itself to the developing of their pheromones. Stranded sailors were often adopted into large group orgies to refresh local gene pools and helped the other Deltans learn about their home cultures. United by ties of sex and geography, they learned to coexist by necessity; with a bountiful natural resources and a low species birthrate, wars over resources were almost unknown on Delta IV.
Deltans became curious about their moon and wished to see what it was like, so they began to build starships around 1982 and first landed on their moon, Seyann. They learned that their moon, like their planet, had local animal- and plantlife not unlike that on Delta IV. They began to explore the lunar surface, cataloguing the plants and animals located there, quickly learning that each valley in its mountains had its own ecosystem. They traveled to the planet's other moon, Cinera, within ten years and discovered that it was little more than a ball of rock similar to Luna, Earth's moon.
Every aspect of Deltan culture has some form of sexual reference in it from lovers to strangers meeting for the first time. Sexual innuendo and foreplay permeate every conversation on Delta IV. Whether this is a result of the Deltan's pheromones or their history is unknown but what is known is the fact Deltans will have large orgies to reestablish dwindling populations. Intercourse between two Deltans is not simply a physical connection, but also an emotional and psychological one because of their empathy. Deltans engaged in sexual intercourse are able to project images and emotions into their lovers' minds, which is what causes the insanity in most other species. Betazoids and other telepathic races are able to keep their sanity in the long term, but will have a very tenuous hold on their mental facilities in the short term.
Deltans take honesty very seriously. If one were to attempt to lie to a Deltan or to withold part of the truth, the Deltan and his/her family would be highly offended and no person in the immediate area would consider talking to such a person.
However, Deltans also have a very playful side and though they can seem aloof to other species. If one looks under the coolness, one may find a very highly developed sense of humor which may be enjoyed thoroughly by both parties. Some of the younger Deltans also enjoy playing pranks on others, and though their elders may enjoy watching it, they try to teach their children to be calm and collected in the presence of aliens.
Delta IV has had an extremely cosmopolitan society for centuries and has been at the forefront of the fashion and home decorating industries along with Risa for many years. A Deltan that wears too much makeup is almost always an actor in a play wherein the lights are too bright for anything else. Many Deltans are also obsessed with shopping and clothes, no matter if the Deltan in question is male or female.
Deltans are Federation members and thus have access to warp drive, medical technology, and transporters among others. Deltan scientists are attempting to discover more procedures that will allow technology to imitate their empathy's pain relieving qualities.
Federation Credits' are used when necessary in dealing with some other races however money is not used locally. Even before outside contact, Delta IV was a very cosmopolitan world, its inhabitants obsessed with clothes, fashion and shopping. Some of the best fashion designers are Deltan as well as a lot of interior designers and other aesthetic professionals, though many Deltan artists attend the Betazed Art Academy or the Andorian Art Institute. However, the Delta University of Design is one of the better academies for design-oriented careers such as interiors, clothes, and furniture.
In combination with the DUD, normally made fun of by offworlders, fashion design and manufacturing employs some 36% of the Deltan people. All Deltans have a innate love of clothing and shopping, whether male or female, and a love of beauty in the humanoid form. This lends itself to the Deltan designers wishing to compliment and beautify all body shapes and sizes instead of going for more and more skin. Color is used wisely, as are patterns and neutrals. Fashion and hair stylists make up another 11% of the professionals in Deltan society, with another 31% in the furniture industry, importing woods from all over the Federation and creating fabrics and wrought iron and brass for bedsteads and candelabras.
As Deltans prefer to live close together out of habit, their cities are famous for music clubs, restaurants, debating halls, and so on for people to meet and talk.
Deltans believe in seven gods who share the powers of the universe among them such as sunlight/moonlight, earthquakes/storms, wisdom, etc. The Deltans believe that marriage is not necessarily binding and can be married anywhere from 1 to 10 people in their lifetime; as such, marriage rituals are practically nonexistent. The rituals surrounding their gods, however, vary from island to island.
Care must be taken. Use of the systems Starbase recommended for non Deltans. Access to the inhabited moon and planet restricted with use of an ' inhibitor shot'. Strenuous exercise is also suggested. Where Deltans mix with other species the should use lotions which help to block most of the effects of their pheromones as well as practice self mindfulness techniques similar but not the same as those practiced by Vulcans. It should be noted however that Deltans are an extremely peaceful species who will 'feel' the pain of others they are close to so will avoid causing any whenever possible.
They also have the ability when touching another to relieve pain, though this is not a physical relief, more soothing. For these reasons they make excellent medics second only to Betazoids.