This is a fork off the locked thread here: https://www.physicsforums.com/showthread.php?t=648423, and is further a response to a recent blog entry 'Does Gravity Gravitate?' (not sure of the PF rules on blogs re threads so won't post a link to it here). The blog presents well what is doubtless a standard argument for why gravitational field is not self-gravitating in GR. One key consequence of that position holds that given ∇aGab=∇aTab=0, the only means whereby the net gravitating mass M of some 'isolated' system can change is via a flux of non-zero Tab stress-energy-momentum in or out of that system. But it seems not hard to readily refute that fundamental GR dogma. Although not widely known, it is well known that a small but finite fraction of the energy pouring out from say a stellar body is owing to HFGW's (high-frequency gravitational waves) as a consequence of thermal jostling between particles [Moderator's note: unacceptable reference deleted; acceptable reference needed.] This entirely random but overall quite smooth and isotropic outgoing flux of non-Tab energy has an obviously insignificant perturbation on the metric at any given time, yet over time represents a steady conversion from and loss of Tab source. This must be so given argument in that closed thread that all forms of gravitational field - including GW's, are not part of Tab. Thus the continuity eq'n ∇aTab=0 cannot be generally correct - unless one wishes to argue that HFGW's are produced 'for free' - thus a further violation of energy-momentum conservation in order to avoid violation of Tab conservation. In that case one has to ask how it is that the Hulse-Taylor binary-pulsar orbital decay data is cited as evidence in favor of both GR and the GW's it predicts, if energy-momentum accounting is not central to that evidence. In that other thread I had cited null Nordtvedt results (involving both Lunar and binary-pulsar observations) as a further line that strongly implied gravity does indeed gravitate, but above single point involving conversion to HFGW's aught to suffice for now. Comments?