We got our dog, Mac, desexed when he was 5 months old. Being a male dog its not like we had to deal with unwanted litters or a female on heat etc but our concern was for the other dogs. Imagine Mac at the beach, an entire female maltese comes along, Mac gets a little bit over excited. 6 months later we are at the beach and there is the little maltese female, with 4 little puppies running after her, with the exact same markings as Mac.....hmmmm......"that wasn't my dog"
Its a contentious issue though since there was a rather large female white something-or-another at our local off leach beach last weekend. Our dog was playing with it, as he does with all dogs.....and the owner came and chastised us saying that the female was on heat and they didn't want male dogs around it. We then explained that our Mac was desexed but they still moved to another part of the beach. I watched and saw other male dogs "checking the female out".....
Now its fair enough the owner being protective of his ***** on heat....BUT....if you are that paranoid about it DON'T take it to an off leash area.....I mean, there are no signs saying "your male dog must be desexed to enter this beach". And as for a female dog who got impregnated by a male dog at such an area I have noone to blame but the owners of the female. Taking a female dog ON HEAT to a off leash area is just asking for trouble IMHO.....