  We review the status as regards the existence of three- and four-body bound
states made of neutrons and $\Lambda$ hyperons. For interesting cases, the
coupling to neutral baryonic systems made of charged particles of different
strangeness has been addressed. There are strong arguments showing that the
$\Lambda nn$ system has no bound states. $\Lambda\Lambda nn$ strong stable
states are not favored by our current knowledge of the strangeness $-1$ and
$-2$ baryon-baryon interactions. However, a possible $\Xi^- t$ quasibound state
decaying to $\Lambda\Lambda nn$ might exist in nature. Similarly, there is a
broad agreement about the nonexistence of $\Lambda\Lambda n$ bound states.
However, the coupling to $\Xi NN$ states opens the door to a resonance above
the $\Lambda\Lambda n$ threshold.
