Don't overthink it; 86% of men ultimately leave no descendants:

Fudan University studied a genealogy of a wealthy family from the Qing Dynasty, from the seventh year of Shunzhi to the sixth year of the Republic of China, over two hundred and sixty years, recording more than twenty generations—
And guess what? 86% of the branches ended without leaving a single name.
Out of a hundred branches sprouting and spreading, fewer than fourteen managed to pass their lineage into the Republican era.
This genealogy comes from the Songyuan Wei family in the northwest mountainous region of Fujian, a local clan patriarch.
When they first systematically compiled the genealogy in the seventh year of Shunzhi, the family started with 169 adult males, establishing 169 independent branches.
The clan had strict registration rules; every male’s birth, marriage, and offspring details were faithfully recorded, with no signs of tampering, making it a complete sample for studying population growth during the Qing Dynasty.
Many believe that wealthy families with abundant land and large populations naturally expand their lineage, but real data shatters this illusion.
Researchers found that the Wei family’s branches began to be eliminated from the very first generation.
Among the 169 branches, 74 ended in the first generation, with a淘汰率 (elimination rate) of 43.8%.
Most of these were due to early death or not marrying and having children in adulthood.
Under ancient medical conditions, infant mortality exceeded 30%, and even those who survived childhood often couldn’t continue the bloodline due to health reasons—this was the main cause of branch extinction.
By the third generation, the cumulative淘汰 (elimination) rate reached 71.6%, meaning over 70% of branches had completely lost their lineage within just a few decades.
The remaining branches also did not all escape extinction; internal resource distribution was a key factor.
As a wealthy family, the Wei clan divided into legitimate and illegitimate lines.
The legitimate branches could inherit ancestral property, shops, and communal resources, giving them the confidence to survive disasters and marry and reproduce smoothly.
Illegitimate branches could only receive small plots of land; in times of drought, flood, or locust plagues, the farmland in mountainous areas would be completely lost, quickly depleting their resources, making it impossible to marry or raise children, leading to branch extinction.
Some branches were expelled from the clan due to internal conflicts over interests, pushed out of the ancestral settlement, losing clan support, and ultimately disappearing while wandering.
External wars and migrations also accelerated branch extinction.
Although Songyuan Town was a closed river valley basin, less affected directly by outside forces, the Taiping Heavenly Kingdom movement and Nian Rebellion during the Qing Dynasty still impacted Fujian’s mountainous areas.
Many male members of branches were conscripted or died in war, leaving only the words “died in war” in the genealogy, with no further records.
Others migrated to Southeast Asia or other provinces to escape war and disaster, losing contact with the clan.
When compiling the genealogy, they could only mark “migrated abroad, no record,” and these branches were considered completely lost.
Traditional clan inheritance rules also led to some branches being eliminated.
The clan only recognized patrilineal legitimate inheritance; if a branch had no male heirs, even if children from collateral lines inherited the family estate, they no longer belonged to the original branch, and its lineage was considered broken.
This rule meant that many branches without biological sons, even if they had successors, could not remain part of the original lineage.
By the sixth year of the Republic, during the last genealogy revision, only 23 of the original 169 branches remained, with a淘汰 (extinction) rate of 86.39%, closely matching the 86% in the research data.
These surviving fewer than 14% of branches were not the most prominent or powerful; instead, they were those that maintained small ancestral holdings, avoided internal conflicts, and lived low-profile lives.
They avoided wars and disasters, and through simple survival, continued their bloodline.
While organizing the genealogy, researchers mostly faced blank family trees or cold words like “no heirs,” “died,” or “migrated, no record.”
Over 260 years and more than twenty generations, the lively family expansion ultimately left only traces of a few branches.
This is not unique to the Wei family; Fudan University’s studies of other Qing Dynasty families show that among the 160 million people at the start of the Qing, most gradually ended their line within two hundred years.
The vast population at the end of the Qing Dynasty was essentially descended from a small number of early ancestors.
Today, when we look at our own family trees, most can only trace back three or four generations; earlier branches are mostly lost.
People often think their bloodline is long and continuous, but under the test of time, extinction is the universal reality.
After the sixth year of the Republic, the Wei family genealogy was locked in a wooden cabinet in the ancestral hall.
Among those vanished branches, perhaps descendants are thriving in unfamiliar places, but they will never know that their names should have been recorded in this genealogy spanning over two centuries.