The basic unit of Great Dragon society, analogous to a human family, is the clutch, a group of 5-7 dragons that were hatched together. Clutch-mates are bonded together emotionally and psychologically — dragons will kill for their clutch, suffer for their clutch, and even die for their clutch.
There are no inter-generational bonds, sibling bonds, or pair-bonds in draconic society, no parents, siblings, or lovers. There is only the clutch, only their clutch-mates. A clutch is born when the dragons are hatched together, and dies when they pass from this world (or when it is shattered). Clutches may ally with each other, but such alliances will never be as close or as lasting as the bonds within a clutch.
(Only Great Dragons form clutches, and nearly all Great Dragons belong to a clutch. There are lone dragons, but such beings are pitied and feared. They age much quicker than other dragons, and are prone to disease and deformity. More, they are prone to erratic behaviors, including total social isolation (an extreme aberration, as all Great Dragons crave the respect of their peers). Absent the bonds of a clutch, dragons are capable of nearly anything. Other dragons fear and avoid the loner.)
Unlike families, clutches are not accidental. They are crafted. An older clutch will purchase or steal eggs from other clutches, and when they have assembled 5-7 eggs of various strains (the ideal clutch has 7 dragons of different and rare strains), will quicken the eggs, place them in a nest, and allow the eggs to hatch. The newly hatched dragonlings imprint on each other within moments of emerging from the shell, and the clutch is born. Clutches cannot add new members, all there are at the beginning is all there will ever be.
Clutches are temporary arrangements. As dragons die or are killed, their numbers dwindle, and when all are dead, the clutch will cease to exist. More, as their numbers dwindle it becomes ever more fragile.
A 4-dragon clutch is a weak clutch, and they tend to quickly break down into lone dragons. (With the infirmities and strangeness noted previously.) A clutch of 8 or more is also a weak clutch, and never deliberately created as it would break down quickly.
If, for some reason, 8 or more dragonlings are born in the same nest, the larger and more powerful dragonlings will gang up on the smallest and weakest, slaying them, until there are 7 or fewer left. In those cases where the weaker dragonling is spared, they often turn out to be an unusually powerful, frequently a spellcaster of great renown.
Dragons can only breed within their strain. Dragons are hermaphroditic, they chose which sex they will be at the time of mating. Mating is a purely practical matter, dragons bargain with each other for mating privileges. The female is the buyer, they are buying a fertilized egg. (Dragons can produce two or maybe three eggs during their lifetime.)
Once fertilized, the dragon lays the egg. Eggs lie fallow until quickened, they can survive for centuries this way. Quickening involves a Great Dragon swallowing the fertilized egg, and allowing it to pass through their system. Once quickened, an egg will hatch in roughly 20 days. Any Great Dragon strain can quicken an egg, no matter what strain that egg is of.
For the most part, each egg produces one dragon, but twins are not unknown. As multiple births are usually unanticipated, this often results in too many dragonlings in the same nest. As is usual, the more powerful dragonlings slay the smaller and weaker.
The clutch is all to a Great Dragon. It was present from just after its birth, and lasts the rest of its life. The breakdown of a clutch is a traumatic event, deeply scarring, and tends to unhinge the dragon. As Great Dragons are nearly-unkillable, genius-level, dinosaur-sized, armored flying death machines, the thought of an insane one is somewhat unsettling.