  Let G be a simple undirected graph with no isolated vertex. A paired
dominating set of G is a dominating set which induces a subgraph that has a
perfect matching. The paired domination number of G, denoted by {\gamma}pr(G),
is the size of its smallest paired dominating set. Goddard and Henning
conjectured that {\gamma}pr(G) {\leq} 4n/7 holds for every graph G with
{\delta}(G) {\geq} 3, except the Petersen Graph. In this paper, we prove this
conjecture for cubic graphs.
