SB 3.26.57

retas tasmād āpa āsan
 nirabhidyata vai gudam
gudād apāno ’pānāc ca
 mṛtyur loka-bhayaṅkaraḥ
Synonyms: 
retaḥ — semen; tasmāt — from that; āpaḥ — the god who presides over the waters; āsan — appeared; nirabhidyata — was manifested; vai — indeed; gudam — an anus; gudāt — from the anus; apānaḥ — the organ of defecation; apānāt — from the organ of defecation; ca — and; mṛtyuḥ — death; loka-bhayam-karaḥ — causing fear throughout the universe.
Translation: 
After this, semen (the faculty of procreation) and the god who presides over the waters appeared. Next appeared an anus and then the organs of defecation and thereupon the god of death, who is feared throughout the universe.
Purport: 

It is understood herewith that the faculty to discharge semen is the cause of death. Therefore, yogīs and transcendentalists who want to live for greater spans of life voluntarily restrain themselves from discharging semen. The more one can restrain the discharge of semen, the more one can be aloof from the problem of death. There are many yogīs living up to three hundred or seven hundred years by this process, and in the Bhāgavatam it is clearly stated that discharging semen is the cause of horrible death. The more one is addicted to sexual enjoyment, the more susceptible he is to a quick death.