Changes how gender is used in the simulation.
The default gender of a simulation is "no". To add gender
to the simulation, run this function with "yes_sys" or
"yes_rand". The value "yes_sys" will systematically assign
gender to newly created individuals as first male, then female.
Thus, odd numbers of individuals will have one more male than
female. The value "yes_rand" will randomly assign gender to
individuals.
Arguments
gender
acceptable value are "no", "yes_sys", or
"yes_rand"
force
should the check for a running simulation be
ignored. Only set to TRUE if you know what you are doing.