Do fermions and bosons produce the same gravitational field?

We examine some cosmological consequences of gravity coupling with different strength to fermions and bosons. We show that this leads to a different perturbation of the standard picture of primordial nucleosynthesis than the addition of extra neutrino types or overall scaling of the value of G. Observed abundances of deuterium and He-4 place bounds on the ratio of the bosonic gravitational constant (G(B)) to the fermionic gravitational constant (G(F)) of 0.45<G(B)/G(F)<0.92 at 1sigma and 0.33<G(B)/G(F)<1.10 at 2sigma. A value of G(B)<G(F) can reconcile the current "tension" between the abundances of deuterium and He-4 predicted by primordial nucleosynthesis. We comment briefly on other cosmological effects.