From Lords of Silence novel:
It’s odd, how a Legion works. Many of the Lords of Silence are Barbarans, taken from the gene pool of that mist-wreathed hell planet. A slim majority, though, are not. Most of the non-Barbarans were created in the Eye from stolen gene-seed, implanted by the Surgeons into screaming infants wrenched from feral Imperial planets, and thus have no connection with the forgotten home world. Others, like Dragan, are turncoats and renegades, refugees from distant Imperial Chapters and warbands. Somehow, though, over time, they all adopt the taciturn habits of Mortarion’s own.
With no words it is mentioned that there are new Lords of Silence from their own gene-seed. It can therefore be assumed that there are no more new Death Guard Space Marines.
Like all the Traitor Legions, however, the Emperor's Children's gene-seed is now so corrupted and riddled with Chaos mutations that it is functionally useless for creating new Astartes. As such, the Emperor's Children, if they could pull themselves away from their self-indulgences long enough to care, must steal pure gene-seed stores from the Loyalist Space Marine Chapters when the opportunity presents itself if they seek to increase their numbers.
From the Fandom article on Emperors Children
Fabrikus was a brilliant Apothecary in the World Eaters Legion during The Great Crusade and served with its First Company, where he gained distinction as a warrior and as a surgeon.
Fabrikus would eventually be charged by the dark masters that commanded him with creating more Chaos Space Marines for their Long War against the Imperium, and he spent several centuries experimentally implanting various species with the Gene-seed available to him in the Eye of Terror. He met with constant failure, however, as the Gene-seed refused to take, or else produced unhelpful mutations in his subjects. Though he would never say this to his masters, Fabrikus came to believe that the Warp caused potency problems with the Gene-seed from their warriors and would not produce the results expected of him. In order to rectify the problem, Fabrikus has decided to hunt down and harvest the Gene-seed from Space Marines loyal to the Imperium, whose belief in the Emperor ensures their Gene-seeds are free from the taint of Chaos. With the Gene-seed taken from Space Marines, Fabrikus is confident he will have the material needed to create a new type of warrior, completely loyal to the Chaos Gods and unstoppable in battle.
From the Lexicanum article on Fabrikus
With that, it can be assumed that the World Eaters are not capable of creating any more Marines with their own gene-seed. It would also imply the same for other Chaos Space Marines legions.
Magnus was unquestionably the most profoundly mutated of the Emperor's Primarchs, both physically and psychically, and the Legion imprinted with his gene-seed reflected that with a high percentage of Thousand Sons manifesting some level of psychic ability. Early in the Legion's history a small, but significant percentage were prone to physical mutation, but in the wake of falling thrall to Tzeentch that percentage escalated wildly. The Rubric ended that forever for the battle brothers of the Thousand Sons, but the sorcerers who command those armoured shells still carry the gene-seed of their Daemon Prince, and wear their grotesque mutations proudly as tokens of their mercurial patron's favour.
From the Fandom article on the Thousand Sons
There are still TS marines with the gene-seed. But it would seem that they're mutated and with the article on Fabrikus, it can be assumed that they can't create any more Space Marines from their original stock.