**There are some unusual anomalies with portal use to enter Earth life, including that when Earth's departure portal is activated, the very next destination cycle after Earth is never the Origin dimension. **
Those within the Origin dimension well understand the mechanism and processes of their common portal use to various numerous destinations, and prepare their portal travelers subconsciously for what to expect on arrival in that dimension (approximate fetal growth and incubation time, birthing method, likely atmosphere at birth, etc.). There is however, a special deviation in portal use in that whenever destination Earth is chosen, they recognize that those people never return to Origin dimension immediately upon departure from Earth.
Rarely, people return to Origin dimension after one other dimension cycle, most after several other cycles, and some only after many, many other dimension cycles. There are some who have still not returned. None ever return directly from Earth to Origin after one cycle, and portal usage cannot be tracked until they return to Origin. Because of this and other unusual anomalies seen with Earth destination portal use (usual between-dimension communication is disrupted for people within Earth dimension; it is extremely complex and rarely easily perceived), there is an off-shoot of portal travel study that specializes on this destination.
Through the millennia, the portal travel patterns of people who chose Earth destination and eventually returned have been studied extensively. These studies have identified one anomaly where, for some unknown reason, anyone choosing to intentionally activate the departure portal from the Earth dimension prior to Earth dimension's naturally occurring exit-portal activation protocols (death) are those that experience the highest number of additional Earth dimension cycles prior to their return to Origin.
For the majority of Origin portal travelers, this is a huge deterrent to dimensional travel, for various reasons, including the fact that most of them do not want to risk being limited to only one dimension for so long, and even possibly for always. Because some very high-value experiences have been reported from the Earth dimension experiences that have not yet been found within any other dimensions, portal specialists have devised a method that seems to have greatly reduced this risk through additional subconscious programming. They are now including additional programming with a very simple basic protocol that embeds at a preeminent level into the Earth life-forms: extremely strong individual survival drive.