  Two groups have independently reported the possible detection of
extragalactic deuterium in the absorption spectrum of the same high redshift,
low metalicity QSO. Although the high value for the inferred deuterium
abundance poses no problems for cosmology (i.e., big bang nucleosynthesis), it
is in apparent conflict with solar system observations of deuterium and
helium-3. This latter inconsistency is explained and made quantitative and it
is shown that, unless the inferred D/H ratio is too high by a factor of three,
these data challange our understanding of the stellar and galactic evolution of
helium-3. This conflict is resolved if the observed absorption feature is, in
fact, due to a hydrogen interloper rather than to high z, low Z deuterium.
