Weapon is a human with special ability to turn into some kind of weapon (scythe, sword, gun, even chainsaw, etc). Some people (not so many it seems) have this ability, others don't. I won't spoil the origins of this ability though, as it's not that important to your question.
Maka's father has it, he turns into a black scythe. He's one of now 9 Deathscythes - those Weapons who ate 99 evil human souls (of those former humans who's abandoned the path of humanity) and 1 soul of a witch; he's the strongest weapon among them and the only one deemed by Shinigami-sama good enough to actually bear the name 'Deathscythe' (that's how he's addressed to by majority of others, even though his real name is Spirit Albarn).
Maka's mother, Kami, is a Meister and she was his second Meister partner (she became his partner sometime after their daughter Maka was born, that is after Spirit turned 18 and presumably after they married). She was the one to turn Spirit into a Deathscythe.
Spirit's first Meister partner was Franken Stein who is coincidentally the strongest Meister to ever graduate Shibusen and considered to be a genius (that's why Shinigami-sama asked him to return to his side to Shibusen). Stein is somewhat younger than Spirit, although it's yet to be revealed by how much, judging by the look when they were kids he's younger by 2-3 years. He and Spirit were partners for 5 years.
Thus, Maka's father is a Weapon and her mother is a Meister, so in theory Maka may possess this special weapon gene and now it may be just dormant (hypothetically mind you asnothing was said about it in manga), but she chose to be a Meister anyway (one of the reasons for this might be the fact that she adores her apparently strong-willed and determined mother and is irritated with her father for his pathological womanizing).
And now my own question: am I the only one here who finds it utterly strange that Stein being such a beast hadn't made Spirit into a Deathscythe even though they were partners for whole 5 years?!
Maka managed this feat in like less than a year!
And Stein was always a beast as seen in flashbacks... what's with this inconsistency I wonder...
Maybe Soul will find some new abilities. The only downpoint is a month-long wait ahead 
and the new Spartoi outfits show nada. I miss Tsubaki's old outfit.
