  From the observations of the anisotropies of the Cosmic Microwave Background
(CMB) radiation, the WMAP satellite has provided a determination of the
baryonic density of the Universe, \Omega_b.h^2, with an unprecedented
precision. This imposes a careful reanalysis of the standard Big-Bang
Nucleosynthesis (SBBN) calculations. We have updated our previous calculations
using thermonuclear reaction rates provided by a new analysis of experimental
nuclear data constrained by $R$-matrix theory. Combining these BBN results with
the \Omega_b.h^2 value from WMAP, we deduce the light element (4He, D, 3He and
7Li) primordial abundances and compare them with spectroscopic observations.
There is a very good agreement with deuterium observed in cosmological clouds,
which strengthens the confidence on the estimated baryonic density of the
Universe. However, there is an important discrepancy between the deduced 7Li
abundance and the one observed in halo stars of our Galaxy, supposed, until
now, to represent the primordial abundance of this isotope. The origin of this
discrepancy, observational, nuclear or more fundamental remains to be
clarified. The possible role of the up to now neglected 7Be(d,p)2\alpha and
7Be(d,\alpha)5Li reactions is considered.
