  We point out that heavy fermion production through the fusion of the
longitudinal gauge bosons might be relevant in probing the strongly interacting
symmetry breaking sector of the electroweak interactions, by showing the
dependence of the one loop amplititude for ($ w^{+} w^{-} \rightarrow
\overline{t} t $) on the symmetry breaking mechanism. The one loop amplitude
for ($ w^{+} w^{-} \rightarrow \overline{t} t $) is calculated for the standard
model and extended technicolour theory. Techni-rho meson exchange is also
briefly discussed.
  We find at $m_{t} = 150 ~GeV$ the cross section of top pair production in $
e^{+} e^{-}$ collisions is comparable in order of magnitude to that of the
longitudinal gauge boson scattering.
