Males vs Females
Many people believe that female dogs make better pets...female preference seems to be ingrained in these people.  Most calls for dogs as pets people are wanting a "sweet girl"  They don't think that females display the alpha behaviors like "marking" and or "humping".  They believe that they are more docile and attentive and do not participate in fighting.  Well folks, this is not true.

In the dog pack makeup, females usually rule the roost and determine the pecking order.  The females as a result are more independent, stubborn, and territorial than their male counterparts. The females are much more intent upon exercising their dominance by participating in alpha behaviors such as humping.  This is a reason people utilize the technical dog term of "bitch" in a negative way and it refers directly to the behaviors exhibited by the females of the dog world.  Most fights will usually break out between 2 females.  Males on the other hand are usually more affectionate, attentive, and more demanding of attention.  They are very attached to their people.  They also tend to be more steadfast, reliable, and less moody.  They are more outgoing, more accepting of other pets, and are quicker to take to children.  Most boys are easily motivated by food and praise and so eager to please that they are housetrained easily.  However males can be more easily distracted during training because the like to play so often.  No mater what age he is more likely to act silly and be more puppy like than the female.  Boys are funloving until the day they die.  Girls tend to be more reserved or dignified as they age.

Boys do tend to get a little bigger that girls.  Neutered males rarely exhibit the behavior of marking or humping.  Once the testosterone level recede after neutering most of these behaviors will disappear.  Boys who are nuetered early (by 5 months of age) usually don't every raise their leg to pee.

As for females she will usually come to you for attention but when she has had enough she will move away.  As for males they are always waiting for your attention and are near at hand. 

Before deciding on male or female give careful thought to other animals and people in your home.  A female usually only bonds with one person (usually the main caregiver) and a male tends to bond with the whole family.

These are for dogs that are not spayed or neutered.  If you spay a female before her first heat she will tend not to have these behavior hormones present.  If you do not intend to breed you dog the best thing to do is have them fixed at around 4-5 months of age.