Two-stroke? :^|
The Bible does not say anything specifically about masturbation for either men or women (though Corinthians 6:9 may allude to it in Greek), but the “lustful” interpretation of the act is commonly given by conservative Christians as the reason for considering it to be a sin (see the recently publicized comments of Christine O’Donnell).
My question for anyone who has that take, though, is what if you’re thinking about your spouse while you do it? It’s not a sin to lust after your spouse, and it isn’t adulterous in spirit.
Wikipedia’s take on Catholicism’s take on lust.
But I’m not sure what are the
.
But they are keeping it to matrimony.
Do us single guys skate on this one? 
Yes and no. If it’s a woman masturbating by herself, it is. However, a husband can stimulate his wife or she can stimulate herself to climax during foreplay, intercourse and afterplay(?) during sex, although that’s not exactly masturbation since there are two people involved.
Ever heard of menstruation ?
I was thinking about this as well. I would be suprised if the folks who see this as a sin would even consider the likelihood a married person would want to masturbate. And heavens to Betsy if a married person masturbated and was thinking of anyone other than their spouse.
Which is the seed, the egg (yes) or the sperm (no)? Some of my christian friends have trouble with this. God, it seems, says that the man contributes the seed. End of story.
According to whom?
That was the belief in OT Biblical times. They didn’t know women had eggs. They thought the dude put his seed in her and a baby grew from the seed. That’s why the Bible always talks about men doing the “begetting,” and rights of succession being passed down through male “seed.” They thought the women were basically just flower pots for male seed.
I remember being told (delicately) in catholic school that “nocturnal emissions”, as long as one didn’t help them along, were not a sin.
Hmmm. Do girls experience the female equivalent? I don’t know for sure, but I asume so.
What would they be emitting? Nocturnal emissions are the male body’s way of discharging excess seminal fluid. The body doesn’t stop manufacturing jizz, it has finite space to store it and the excess has to go somewhere. If it is not discharged through sex or masturbation, the body will offload it itself.
I’m not aware of any analogous female need. They obviously have dirty dreams, but those are not equivalent to nocturnal emissions, and even a lot of male nocturnal emissions do not correlate to sexual dreams.
Up till “The Awakening” beginning in the late 50s or so it was believed by many that women didn’t experience orgasm during sex. I suspect they “onan’d” a lot. 
I was born in 1945, so I rember that era pretty well.
What was that author’s name? Judith something? She was (in)famous for writing on the subject.
Boys called it “wet dreams”. They did, if I recall correctly, feel good.
Neither boys nor girls would have actual erotic dreams because they had no experience to base them on.
Not sure how much onan they actually got - from Galen onwards, the standard treatment for “hysteria” (read: massive female blue balls syndrome) involved manual stimulation by a physician or midwife and later on vibrators and proto-shower nozzles.
Presumably if wimmin had to call in a doctor to get off they didn’t quite grok how to do it themselves, or perhaps felt if it was someone else doing the rubbing it wasn’t quite as sinful.
Hilariously, the Wikipedia entry states :
The times, they have a’changed.
When I was an adolescent, I had dreams which, in retrospect, were extremely inaccurate, but which nonetheless seemed plenty erotic to me at the time. And for that matter, a lot of erotic art produced by people who do know about the real thing is completely unlike reality, too.
There’s some argument that the Bible actually includes oblique references to masturbation. I can’t remember the specifics, but it has to do with King Saul relieving himself in a cave, or something.
When did Jews start to count Jewishness through the mother’s line?
Since pretty much always, it’s halakha, but that has more to do with being able to know for sure who the mother actually is than with any understanding of genetics.
You know there are still a lot of guys who aren’t about to buy this mother/seed thing.
They’re out there right now, sowing wild oats.
Flower pot! That’s good. 
Just like in California!
“Hey Josephus the healer… I need another holy writ for some righteous weed.”
“Are you sick?”
“Yeah, I’ve got…a small newt playing havoc in my stomach!”
“Very well. Here is your writ.”
“Can you make it for some Lebanese blonde hash? That works REALLY well with newts.”
“It is done. Peace be with you.”
“Peace, man.”