This is were one needs a montage of all of those shelter commercials of all the sad, unwanted, abused animals in over crowded facilitiesI second the take them to a shelter opinion. Make them look at the dogs who have to "make space" for the next generation they inntend to produce.
Every shelter I know takes and welcomes volunteers. One afternoon could change everything. If they can see a happy, friendly, waggly tailed dog about to die from lack of space and still produce more... Find better friends.
I cry every time...
I think a shelter visit will definitely drive the point home.