  We study a linear model of McKendrick-von Foerster-Keyfitz type for the
temporal development of the age structure of a two-sex human population. For
the underlying system of partial integro-differential equations, we exploit the
semigroup theory to show the classical well-posedness and asymptotic stability
in a Hilbert space framework under appropriate conditions on the age-specific
mortality and fertility moduli. Finally, we propose an implicit finite
difference scheme to numerically solve this problem and prove its convergence
under minimal regularity assumptions. A real data application is also given.
