  Nearby star-forming galaxies offer a unique environment to study the
populations of young ($<$100 Myr) accreting binaries. These systems are tracers
of past populations of massive stars that heavily affect their immediate
environment and parent galaxies. Using a Chandra X-ray Visionary program, we
investigate the young neutron-star binary population in the low metallicity of
the Small Magellanic Cloud (SMC) by reaching quiescent X-ray luminosity levels
($\sim$few times $10^{32}$ erg/s). We present the first measurement of the
formation efficiency of high-mass X-ray binaries (HMXBs) as a function of the
age of their parent stellar populations by using 3 indicators: the number ratio
of HMXBs to OB stars, to the SFR, and to the stellar mass produced during the
specific star-formation burst they are associated with. In all cases, we find
that the HMXB formation efficiency increases as a function of time up to
$\sim$40-60 Myr, and then gradually decreases.
