The creation of a new Space Marine relies on the Gene Seed harvested from existing Astartes. According to the Wiki - Creation process

Progenoids: Phase 18: There are two of these glands, one situated in the neck and the other within the chest cavity. These glands are vitally important and represent the future of the Chapter, as the only way new gene-seed can be produced is by reproducing it within the bodies of the Marines themselves. This is the implant's only purpose. The glands absorb genetic material from the other implanted organs. When they have matured, each gland will have developed a single gene-seed corresponding to each of the zygotes which have been implanted into the Marine.

These take time (5 years in the first case, 10 in the latter) to mature into gene-seed. The gene-seed can then be extracted and used to create more Space Marines. Thanks to the superior implantation process and genetic stability of Primaris Space Marines, the Imperium has recently been able to harvest gene-seed at a rate previously unseen.

Does this mean each successful Space Marine can provide Gene Seed for a maximum of two others? After 10 years both Progenoids can harvested, and the Marine no longer contains any Gene Seed?

  • 1
    Progenoids are only harvested after the death of the SM. I think to remember a chapter harvesting the Progenoid in the neck after 5 years and in the chest after death. Need to check however. I can't remember that progenoids are reimplanted after being harvested.
    – Shade
    Commented Oct 11, 2019 at 10:17

1 Answer 1


No. From the Deathwatch - Core Rulebook, page 18:

In the penultimate phase of the process, a pair of glands called Progenoids are mplanted, one in the neck and the other deep in the chest cavity. This takes place between the age of sixteen and eighteen. These glands are vitally important to the very survival of the Space Marine’s Chapter. Each organ grows within the Space Marine, absorbing hormonal stimuli and genetic material from the other implants. After five years, the neck gland is mature and ready for removal. After ten years, the chest gland becomes mature and is also ready to be removed. A gland may be removed any time after it has matured, and it represents the Chapter’s only source of geneseed. When mature, each organ contains a single gene-seed corresponding to each zygote implanted into the recipient. Once removed by surgery, the Progenoid must be carefully prepared, its individual gene-seeds checked for mutation, and sound gene-seeds stored. Gene-seeds can be stored indefinitely under suitable conditions.

Space Marine Apothecaries carry a special device known as a reductor, which they can use in battlefield conditions to remove the Progenoid glands of a fallen Space Marine, so that, even should he die before his glands are harvested, they may be recovered. The whole purpose of the Progenoid is to provide gene-seed to enable the Chapter to continue. It is not possible to create a zygote in any other way. Each Chapter’s stock of gene-seed is therefore unique to itself. Gene-seed has a great deal of religious significance to a Chapter, representing its identity and future. Without gene-seed, a Chapter has no future. The extinction of a type of gene-seed means that a zygote has been lost forever. The extinction of the Progenoid gene-seed itself would effectively mean the end to a Chapter.

As each Space Marine has only two Progenoid glands, the rate at which a Chapter can create new Space Marines is restricted. It may take many years for a Chapter to rebuild itself after heavy losses. Gene-seed is often rendered useless if a Space Marine is exposed to high radiation levels or other forms of genetic disturbance. The efficiency of different Chapters’ Progenoid gene-seed also varies, so some Chapters are able to make up their numbers faster than others.

From the Grey Knights Grand Master article:

Grand Master Epimetheus - One of the original Founding members of the Grey Knights, Epimetheus stood before the Emperor alongside the other seven potential recruits that Malcador the Sigillite had selected in the hours before the start of the Battle of Terra, and was given command of the 5th Brotherhood. Originally a Legionary of the Dark Angels Legion, he served on Caliban under the Arch-Heretic Luther. Regardless of how Epimetheus became a Grey Knight, his original Progenoid Glands were removed and sealed in a stasis capsule beneath Titan along with the gene-seed of all the already-implanted recruits. It was then replaced with the new gene-seed set aside for the foundation of the Grey Knights.

So, apparently, there is a possibility to remove the Progenoid Glands and add new ones. As Abaddon captured Epimetheus when he wanted to open the Damnation Cache, it is probably described in the Pandorax Novel. I haven't read the novel yet. I.e., it is possible for Astartes to "donate" a fully matured gland every 5 years. If this is a standard procedure, I do not know. With the limit of 1'000 Astartes, it is useless for a chapter to have too many "ripe" glands. It might be usefull in case a chapter has to rebuild after losses.

Also, non-conform chapters such as the Black Templars might be using this in order to push their numbers.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.