What is the transconductance value of a given bjt?
\$g_m = \frac{I_C}{V_T}\$

where \$I_C = I_S \cdot e^{\frac{V_{BE}}{V_T}}\$

So, \$I_C = 10^{−15} \cdot e^{\frac{0.7}{0.025}}\$

\$I_C = 1.446257 mA\$

Hence, \$g_m = \frac{1.446257 mA}{0.025 V} = 57.850282 mS\$