They have to like each other.  Click on the dog house and choose who you want to have a litter.  If you want to control your pets the cheats are:
boolprop PetActionCancel true (or false to shut off)
boolprop ControlPets on (or off)

Thank You!

Thank You !!!

Very nice job.  Just what I was looking for.  Thank You!!  Thank You !!

Thank you!!

Thank You!!

Thank You!!

Thank you so much, it is very annoying to get those calls all the time.

Thank you for the update.

Thank you so much, I've been running out of ideas.

Thank you so much for keeping us updated!!!!!

Thank You!!!!!

Thank You!!!!

Thank You!!!

Thank You!!!