In this paper we establish some inapproximability results for the
\textsc{Lateral Transfer Problem}. This optimization problem, which was defined
by Hallet and Lagergren, is that of finding the most parsimonious lateral gene
transfer scenario for a given pair of gene and species trees. We will prove
that the Lateral Transfer Problem is MAX SNP-hard; thus Polynomial Time
Approximation Scheme is not possible for it unless P = NP.