Without looking at the obvious place on a dog, is there a way to figure out if it’s male or female? As far as I can tell, there aren’t any distinctive markings or body shapes that indicate the sex of a dog. But I don’t know if that’s just because I’m not recognizing some subtle clues or if there aren’t any clues.
Reach underneath! 
Wait for it to pee.
Squat = girl
Leg lift = boy
Not necessarily. We had a male dog that squatted to pee too. he was a strange dog, admittedly.
A lot of male dogs squat to pee. I’ve seen females that lift their leg as well.
After 15 years of shelter work, I never seen a foolproof way of judging a dog’s sex without leaning down and checking out the package.
Or you can just take a wild guess and let the owner correct you.
The true fun shelter game is trying to discover if the female dog is spayed or not.
Along with what Q.E.D. said, my male Lab is over 14 and can’t lift his leg to pee, so squats a little and lets fly!
Some breeds make it easier, though. Golden retrievers for example (being the only breed I’m actually familiar enough to say this) do look different between males and females. Mixed breeds probably even out, though most of the time I can tell the sex of a purebred Golden. Males tend to be taller, and blockier, with shorter, stubbier noses, and they are much wider across the face and shoulders. Females tend to have skinnier, pointier noses and faces, stand shorter, and are just generally built lighter. A good example of a male golden retriever would be the first link, a female the second:
http://www.photo.net/photo/pcd2488/golden-retriever-6.3.jpg
http://www.stoneleath.com/POF2.html - look at “Kate”, near the bottom of the page. The other dogs are all male.
Again, though, this isn’t fool-proof, but I can usually make a good guess.
Watch 'em play golf, and see what color tees they hit from.
Sheesh…
My boy squats too. I’ve tried teaching by example, but he only looks at me funny.
I have a Great Dane, and knowing Danes, I can generally pick out females from males. Females tend to be smaller, both in height and across the chest. The head is smaller and the skull has softer lines and a small occiput (that knobby bone on the top of the skull). Overall, compared to male Danes, females seem to have a real “feminine” quality to them.
On collies, it’s easy. Remember how Lassie had that magnificent mane? Female collies don’t have that. Why they chose a breed where you could easily tell the difference, and had a male dog play “Lassie”, I have no idea.
Or, to put it another way, why make Lassie a female? Did they just love the name "Lassie"so much they hadto build the show around the dog as a female??
I never knew this about collies, but come to think of it, we had a female collie when I was kid and she didn’t have it.
I don’t think they liked the name so much, but wasn’t that also the name used in the books that the movies were based on?
They bark with a higher pitch and get bitchy once a month?
Don’t know about the pitch of the bark, but a female dog is bitchy all month.