Uncanny X-Men #167

The X-Men return home to Xavier's Institute to find they've been replaced. But their skirmish with the New Mutants is the least of their concerns. Charles Xavier has been impregnated with a Brood Queen. In order to save mankind, the X-Men may be forced to take the life of their beloved mentor. Plus, the Shi'ar Majestrix Lilandra visits a warning on Reed Richards for the crime of saving the life of Galactus