Typically though if you have two plants from a strain that has been stabilized, you can polinate the female and she will produce good stable seeds.
However, if you cross-polinate two strains you can end up with all kinds of different variants. that is why growers cross-polinate, then grow the offspring seeds, find an offspring plant that has the traits they want and then they pollinate it with which ever one of the parent plants that has the traits that they want their final plant to end up with. Then they breed the resulting offspring with each other until further generations of seeds are consistant. That is what stabilizing a strain means.
Hope that made sense....