politics

"If you don't like abortion then don't get one"

This will not convince anyone who's pro-life because they believe abortion is the same as murder. To them it's like saying "if you don't like murdering people then just don't do it".

"If you're a man then just shut up about abortion"

AFAIK, just about every opinion poll that's ever asked the public about abortion has found that men are not really much more anti-abortion than women are. If there is a gender gap, it's like 5 percentage points or less. I think I've even seen one or two polls that show women to be more pro-life than men (but again, not by a big margin). So if there's not a big gender gap on abortion then I don't really see how this talking point is helpful.
Seems to me that the most likely consequence of this argument is it will discourage pro-choice men from participating in the cause & offering support.

(also, fwiw, it's cissexist; trans men exist and can get pregnant)

“Making abortion illegal will not decrease how often abortion happens; it will only drive it underground and make it less safe.”

I don't think this is a good argument. I have a few reasons why:

1. Banning abortion probably will indeed decrease how often abortion happens. After all, bans tend to be fairly effective at getting people to not do things. Just as one example: there are a lot of semi-automatic firearms in the US, but not nearly as many fully automatic firearms. Why? Probably because fully automatic firearms are banned. I don't see why the same wouldn't happen with abortion.
2. If you want another example that is more directly related to abortion: during the Roe era, red states developed a tactic of putting onerous and extremely contrived rules on abortion providers, with the unstated goal of getting those abortion providers to shut down. And it worked. A lot of abortion providers in red states shut down because they couldn't comply with these ridiculous and obviously contrived regulations. Statistics bear out that red states have a lower rate of abortion than blue states. If contrived targeted regulations were effective at reducing abortion, then an outright ban probably would be too.
3. A lot of the time when this argument is made, it's articulated in a way that seems to concede the idea that decreasing the recurrence of abortion would be a good thing, and I'm not sure why we on the pro-choice side should concede that.

"If abortion is murder, then every time a man masturbates is genocide, and every time a woman menstruates is murder"

Most pro-life people are smart enough to know the difference between a gamete and a zygote, so this doesn't convince anyone.

"They're not pro-life, they're just pro-birth" (sometimes phrased as "pro-forced-birth")

Usually this isn't actually an argument for legal abortion, it's just a reference to the fact that conservatives generally oppose social safety nets. Which, yeah, it is shitty of them that they want to force (often poor) people to have children but don't care much about the welfare of those children once they are born... but there's no inconsistency there. It's not a hypocritical position, just a very cruel one. So we shouldn't act like this is some amazing "gotcha" moment.

"If we're gonna ban abortion then how about we force men to start paying child support as soon as the woman gets pregnant"

This is just not an effective argument. Most anti-abortion people would be just fine with this idea. They are more than happy to force their "family values" on men as well as women.
You wouldn't be able to tell from liberal/leftist conversations, but conservatives resent liberal, non-religious, sexually promiscuous men to a similar degree as they resent liberal, non-religious, sexually promiscuous women.

"They're just anti-woman/they just want to control women"

I think there's some truth to this one (conservatives definitely harbor resentment towards sexual activity & expression that they perceive as un-Christian) but ultimately I don't think this is the best argument to use. I don't think that misogyny is really what motivates them. I think they actually are convinced that a just-fertilized zygote is a fully formed person with a soul and a mind and a conscience.

"If men could get pregnant, then there would be abortion clinics on every corner"

1. As stated before, trans men exist and can get pregnant
2. As stated before, there is not really much of a gender gap on abortion, and it is not helpful to imply that there is.

So. What arguments should pro-choice people use?

In my opinion, the abortion issue really just comes down to two main questions:

1. Is an embryo/fetus a person?
2. If it is a person, does that mean it has a right to continue growing in its ~~mother's~~ birth parent's (I guess that's the more correct term) uterus?

And our answers to those questions should be as follows:

1. No, it is not a person. (At least, not until it's developed enough to survive outside the womb - I'm not sure what I think about this exactly)
2. No, it does not have a right to use and benefit from another person's organs

That's really all that we need to say about it, although I have a couple of extraneous thoughts below that might also be useful:

• An embryo/fetus is not a person. It has some of the characteristics of a person, but not all of them. It cannot survive outside the womb because its organs aren't developed enough. Until about 24 weeks of gestation, it can't even feel pain because its nervous system isn't sufficiently developed. It is not sentient. It cannot perceive itself or its environment. It does not have subjective experiences. If it isn't sentient, then it has no interests to protect (which, when you think about it, is basically what "rights" are).
• an abortion is generally defined as "the termination of a pregnancy via the removal or expulsion of an embryo or fetus from the uterus". Notice here that it is NOT defined as "the destruction of the embryo/fetus" or "the death of the embryo/fetus". It is merely the "removal or expulsion". This is why miscarriages are considered by medical professionals to be a type of abortion - specifically they are a "spontaneous abortion". So, even if one considers an embryo/fetus to be a person, an abortion is not actually an act of killing that "person", it is just the act of removing that "person" from the uterus. If the embryo/fetus dies after it has been removed from the uterus, that is a separate event and it is not the doing of the (formerly) pregnant person.