The Half Orc PC

Origins of a Fantasy Bad-boy
White Box provides for players to have characters who are human fighting men, magic users or clerics, or they may choose to make their character a dwarf, elf or hobbit (halfling), although each of those races carry limitations regarding choice of class and level advancement. Orcs in White Box are strictly bad guy monsters (although there is a provision allowing PCs to be virtually any monster race). There is no mention of any half races in the three LBBs.
Supplement I: Greyhawk introduces half elves as the first half anything. Greyhawk was Gary Gygax's home campaign and I assume half elves (ala Tolkien's Elrond Half-elven character) were a part of the Greyhawk milieu. The Advanced game includes half elves and half orcs in both the Monster Manual and Players Handbook (as PC races). Both the Advanced Monster Manual and Players Handbook use the term "mongrel" to describe the half orc pedigree. On the Racial Preferences Table in the PHB, half orcs are listed as hated by dwarves and gnomes, viewed with antipathy by elves and half elves and suspicion by halflings, are tolerated by humans. Good will and preference is generally denied half orcs by the other player races.
Half orcs may pursue life as a cleric (limited to 4th level), a fighter (10th level), a thief (8th level), or an assassin (unlimited) in the Advanced game.  Only as an assassin, an evil character class, are half orcs able to truly excel to unlimited heights of achievement.
The Advanced Monster Manual states that "orcs will breed with anything". The half orc PC is assumed to be human and orc mix as the Players Handbook states, "some one-tenth of orc-human mongrels are sufficiently non-orcish to pass for human." How this inter-breeding of orcs and humans occurs is not explicitly explained in the rule books, although the explanation may frequently involve violence.
The half orc disappears from the 2nd Edition of the Advanced game as a player character race and does not appear in Basic at all. Half orcs are reintroduced in 3rd Edition as a player character race and have remained ever since. Many settings treat half orcs the same as any other race regarding acceptance and likability. This seems to be the implied default for most versions of the game published post 2000.
I have seldom had any interest in playing a half orc character, and in general avoid playing chaotic characters and PCs of evil disposition. I prefer the good guys. Even as a referee, I tend to impose social stigma on half orc characters and even half elves as "strange and different" (in my homebrew campaign). My players know this going in, yet some seem to welcome the challenge. The one half orc PC I have played for some time was handed to me by the referee as "my" character. It was a 3rd Edition campaign which I was joining in progress. I consider it a good experience for me learning to play a character I would not have chosen for myself. Sometimes it is good to go outside our personal comfort levels.