See photographic evidence below.

On the 1st of June at 8:30am Jerry and Pepe were delivered to the hospital by the humans.  At about 9:10am they were anaesthetised - a small patch of fur on the upper front right arm was shaved off for this purpose. 
Between 11am and 12am they each underwent an ovario-hysterectomy (uterus and ovaries were removed) - a large patch of fur was shaved off the middle abdomen to prevent later irritation of the incision.  Pepe's incision required 5 stitches, while Jerry's required 4 stitches.  A tattoo, which looks like a circle with a vertical line through it, was then drawn in each left ear.
After the surgery, a Trovan microchip was implanted, using a syringe and needle, in the area between the shoulder blades.  The microchip numbers will not be disclosed at this time.
It is believed that it was then, while still under the anaesthetic, that Pepe's last stubborn baby canine tooth was removed.  However, this was never confirmed by the surgeon.
The rest of the day was spent sleeping.

No way, we're not going in there.
(famous last words - P&J - 8:30am 01/06/2000)