Werewolves are both wolf and human; these halves of their souls cannote be pried apart or even divided down a sharp line.  Having said that, though, each werewolf is born to a particular breed and raised in a certain manner depending on that breed.  What determines breed?  Simply enough, it's the natural form of the werewolf's mother, whether she is Kinfolk, Garou, ordinary human or wolf.  If she's a wolf, then the offspring is lupus.  If she's human, the child is homid.  And if the mother and father are both werewolves, their progeny is metis.  For example, Fireheart is a lupus Red Talon female.  If she mates with a packmate who is Kinfolk, any Garou she bears would be considered lupus.  And even if Fireheart mates with human Kin while in her two-legged form, any werewolf children from that union are still lupus.  Female werewolves who bear offspring always wear their breed form when giving birth.  The only exceptions to this rule are the unlucky females who bear metis.  If they didn't assume their Crinos forms, they'd assuredly die from the experience.  Note too that every so often, a werewolf child is born to an ordinary human or wolf mother who may be many generations removed from werewolf and Kin.  Gaia alone knows whom to choose as her warriors.

Each breed has its own strengths and weaknesses, and each group has a slightly different connection to Gaia.  For example, many lupus believe that their link to the Wyld is stronger than that of homids.  Then again, some homids become more wolfish than human, while a few of their lupus brethren discover they like living in their two-legged forms.  Homid and lupus alike generally scorn the deformed metis as sick reflections of Gaia's own malaise.  Whatever the case, all three breeds provide interesting hooks for developing unique and flavorful characters.
 

Homid

You were raised a human by human parents, who may or may not have known about the wolf in the Family fold. The Changing blood may have been passed to you generations after the seed was sown. In any case, your true nature was a mystery until puberty, and maybe for some time after that. Nightmares, odd daydreams, and wild urges plagued you. Then, one night, odd visitors appeared to usher you into your new life. Perhaps you were kidnapped and taken to the tribe, or maybe you ran away and were tracked down by your Garou relations. Now your old life is gone, and you must start anew. Though you may well remain in contact with your old family, they are unaware of your nature uless you choose the Kinfolk Background. Trying to explain the truth might get you locked up, so it's best not to try.

Homids have many advantages: they are familiar with human society, can begin the game with any Ability and tend to be better at abstract thought and reasoning. Their connection Gaia's primal essance is thin, however, as evidenced by their low initial Gnosis, and their senses are fairly dull by werewolf standards. They depend more on sight and hearing than on overall perception. Opposable thumbs aside, the natural homid form is generally weaker than that of either lupus or metis. Homids may, however, handle silver without a Gnosis penalty in their native form. Unfortunately, many metis and most lupus resent homids because of their greater numbers and the devastation that their human cousins inflict on Gaia.

Born and raised as a wolf, you puzzle over the actions of the humans and wonder why they refuse to fit into Gaia's order. You probably made a high place for yourself in your pack before discovering your real nature. Then the great wolves came. They took you away to reveal their mysteries to you, and showed you why you never quite fit in.

Your first meeting with humanity was probably violent, and you may very well carry a grudge for some past wrong. Human speech is difficult for you, and human manners are beyond your comprehension. Human devices still make you edgy, and you tend to stand out in a human crowd. In the wild, though, you are a master, and can run circles around most homids. The advantages of your breed include a deep primal connection to Gaia, extraordinary senses, and a strong natural form. Your primary disadvantage is an unfamiliarity with humankind. Because of this, beginning players may not start the game with the Abilities listed above. You often se things in very simple terms ( black or white, no gray areas, as animals do... e.g. 'kill or be killed'), and tend to react instinctively rather than out of reason or logic.

Your parents disobeyed the first tenet of the Litany, and you pay the price. Your body bears the stamp of Gaia's disapproval. Ostracized by most Garou, you have nevertheless been raised among them. Though familiar with the ins and outs of werewolf society, you know more about the dark side of the Garou than anybody ought to know.

Many Garou see the metis as a symbol of Mother's sick state. When the world was pure, they say, metis were few and far between, and usually died young (one way or another.) Now your breed grows in number while the 'pure' Garou dwindle, and the elders have to deal with you, whether they like it or not. Your suffering has shaped you, many metis are proud in spirit and tough in body. Some are noble, compassionate, and understanding, while others inflict their own pent-up Rage on anyone they can.

The assets of the metis are self-evident; your natural form is the powerful Crinos, and your knowledge of Garou society is profound. Many elders feel responsible for you, and will often teach you whatever you need to know. Trained from birth, most metis mater both abstract and raw instinct. Metis characters may arrange their Abilities any way they like, and they need not worry about the initial confusion suffered by newly changed homid and lupus. (Some metis, however, are raised by Kinfolk, given to them by Garou too ashamed to acknowledge their offspring. These unfortunates quickly learn to hide their natural form, but learn little of Garou society.)

The disadvantages of this breed are also obvious; in addition to your pariah status, your body is twisted and deformed in some way. Additionally, all metis are sterile. These deformities are more than just physical hindrances; the Garou see them as outward reflections of Gaia's anger. The fact that many Black Spiral Dancrs are metis (and suffer no stigma because of it) just reinforces this idea. The path of the metis is a long, hard road.

Albino:  You have no melanin in your body, no matter what form you take.  As a result, your skin is faintly pink, and it burns easily, so stay out of the sun if possible.  Your hair is stark white (not silver) and your eyes are blood red, which makes you a real anomaly among the werewolves.  Take a +2 difficulty penalty on all Perception rolls if you're trying to operate in bright light without your protective clothing or sunglasses.

Blind:  Whether you have two eyes in the right place that don't work, or no eyes at all, you are totally blind.  You fail any rolls involving vision automatically.  At the Storyteller's discretion, though, you may take occasional bonuses with other sense groups.

Withered Limb:  You have four limbs, but the muscles of one are atrophied, leaving it withered or paralyzed.  Depending on your form, you can't walk well, and you run more slowly that other werewolves.  You incur a +2 difficulty penalty on all Dexterity rolls when trying to use this limb.

Fits of Madness:  Your curse has unhinged your mind, and you suffer from hallucinations, manic-depression, paranoia, a split personality, or worse. Under stress, you must utilize your willpower rating or succumb to Rage and frenzy. This can be fun for spectators but hell on the pack.

Hairless:  Your body hair is mangy, patchy, or totally nonexistent. You take extra damage from cold and suffer from constant sniffles. In homid form, you look odd. In wolf form, you look downright vile. With this Deformity, you cannot take the 'Pure Breed' background.

No Sense of Smell:  You have no olfactory nerves, so your sense of smell is nonexistent.  This is an unfortunate thing for a creature who relies so much on her nose.  You fail all Perception rolls involving smell automatically, and you suffer a +2 Difficulty penalty to track prey using your Primal-Urge.

Wasting Disease:  Your constitution is notably weak.  You cough and wheeze, and you can't keep up when your pack trots along for hours on end.  Take a +2 difficulty on all Stamina rolls, including soak rolls.

No Tail:  Not having a tail creates serious communication problems with others of your kind.  You take a +1 difficulty penalty in all social situations while in Lupus, Hispo, of Crinos forms.  Likewise, your sense of balance suffers.  You take a +1 difficulty penalty to Dexterity rolls as well while wearing those forms.

Seizures:  You suffer from periodic spells of unconsciousness and loss of muscular control. When in stressful situations, you will usually collapse to the ground, writhing and babbling mindlessly.

Horns:  A pair of horns sprouts from your brow.  They may be like those of a ram or goat, or perhaps you have a small pair of antelope like antlers.  You might even have a single short horn like a unicorn's.  Whatever the shape this disfigurement takes, you suffer a +1 difficulty penalty to all Social rolls, and you are likely to be even more heavily scorned by your fellow Garou.  (Horns are a mark of prey, not of a predator, after all.)  If you actually try to attack with your horns (which may do Strength + 1 bashing damage at best), you will likely lose some amount of Glory Reknown for fighting like a prey animal instead of a Garou.

Hunchback:  Quasimodo...Igor...they don't have anything on you. Your spine is terribly deformed, bent and twisted, and you have an abnormally large hump. Your mobility is severely impaired; and you suffer a decrease of Dexterity. However, odds are that you're powerfully strong to boot.

Tough Hide:  Your thick, leathery hide resists damage, but it also has major drawbacks. You are constantly scratching and picking at your hot, uncomfortable skin. Since your hide is so thick, your hair (or fur, depending on which form you're in) grows out in random tufts, so you have bald spots all over your body, which decreases your Social attribute in all highly social situations.

Weak Immune System:  You tend to get sick and stay that way more often than others in your pack. Your body's natural immune system can't keep up with the stress you subject yourself to, so you are more prone to becoming sick. You do not receive the Bruised Health level, and you may prove susceptible to Wyrm emanations.

Source material taken from Werewolf : The Apocalypse Core Rule Book Second Edition, Chapter Five, pages 86 & 87, and The Werewolf Player's Guide, Chapter One, pages 27 & 28 and from Werewolf:  The Apocalypse Third Edition, pages 59-61

Source Material taken from Werewolf:  The Apocalypse Third Edition; Copyrighted by White Wolf Publishing and Gaming Studios, Incorporated.