Selecting a male vs, female puppy is strictly a personal decision, although the following points should be taken into consideration:
When male hormones really kick in (between 6-12 months of age), he will begin lifting his leg to urinate and marking vertical surfaces (sometimes even furniture in the house). Neutering will help prevent this.
Females usually come into heat twice a year, although some as often as four times a year. Each season lasts 3-4 weeks, during which time males in the neighborhood may be attracted to your house. She will need to wear "britches" for about 10 days. Same bitches experience mood swings during their heat.
Males become impossible to live with when there is a bitch in heat nearby. All they can think about is breeding for 2-3 weeks! They will become more independent, more dog oriented and less willing to obey humans. Some even break through glass windows or claw through wooden doors to breed the bitch.
Females can also become impossible to live with. When they are ready for breeding they too are more dog oriented and less willing to obey humans. They will become very persistent in trying to find a way out of their yard if a male is in the area.
Spaying/neutering does not make dogs fat. Too much food makes them fat! However, it does reduce the incidence of cancer later in life.
Spaying/neutering makes for a better pet, particularly for families with small children. It will make the dog more people-oriented and less likely to roam away with other dogs. Other than that, it won't change their personality.
Some people have the mistaken notion that the dog will not be "satisfied" as an adult if it is not bred. Not true. Males, in particular, take on an entirely different attitude after their first breeding. Most become more dog oriented. As an experienced stud, they become very frustrated and almost impossible to control the next time a bitch is in heat. Females should not be bred just so the kids can see the miracle of birth or because you want just one pup out of her.
There are thousands of pure-bred and mixed breed puppies and dogs abandoned and killed every year because of overpopulation. Only proven, champion-quality animals should be bred. And their breeding should be carefully planned to reduce the chances for passing on hereditary problems, and increase the chances for improving the breed. Just because the animal has champion parents does not make it breeding quality! Look at what overbreeding has done to German Shepherds, Goldens, Dobermans and Cockers, to name a few. For further information about spaying/neutering, check with your vet, breeder and local spay/neuter clinic. Also check with your city or county about reduced fees to license altered pets.