Involving men in birth might involve replacing some taboos with others.
Indeed, rules or taboos for everybody attending a birth would probably need to be invented so that the mother as well as attendants.
These would be mechano-memes to do with what one should and should not do, touch, say and so forth, during a birth. You could start kicking these around, as well as the signal memes, the names and things one says to do with these new replacement taboos.
Another thing to think about might be to build a memetic sub-system like a "bucket list" i.e., that attending a birth would be something that everybody should try to do, i.e., to not be a "birth attendance virgin" or whatever. There would need to be a set of rituals associated with asking people to attend one's birth / maternity, asking to attend, getting invited, who shouldbe invited, and so forth.
Establishing a system of cultural expectations (even if the "culture" is "new") aids acceptance, and failure to do so hinders this, and allows the imuno-memes of the existing system to attack, e.g., characterize the (mechano-)memes of the new system as "irrelevant" "weird" or what-have-you.
If there is a new memetic subsystem, e.g., "my friend is giving birth this month, I should attend", complete with rituals associated with how this transaction / relationship may be conducted, e.g., communicating with the mother and her handlers (maybe having a handler is part of the new memetic system for example), communicating with interested and disinterested others about it, does one bring a gift, what does one wear, what does one say, what names are given to the various actions taking place, and so on, then the system can being to "co-opt" (see my manga) the signal and mechano-memes of the existing system in order to establish itself with as little conflict as possible.
Examples are of how religions take the symbols of established religions for their own purposes, e.g., Jesus Christ, the Christmas Tree, etc., or corporations re-use product names or images or whatever. People already know how they feel about these icons and accept them automatically, and then tend to accept memes which we attach, through reasonable application of accepted rules and processes, to those existing memes, MIAOs and icons.
Another thought, [insert self-deprecating comment here], is that nerds might be early adopters of this new kind of birth-friendly culture. Even "snerds" (pseudo-nerds, imposter-nerds, poser-nerds, etc.) might be good candidates. Nerds are fascinated by complex systems that can be more-or-less well understood, given enough study, especially when those systems give "feedback" that you "got it right".
For example, there was a birth, the expected stuff happened, everybody lived and felt well afterwards, there was messy stuff that happened but I brought appropriate cleaning supplies, change of clothes, and other equipment and dealt with it, and it went well, plus learned stuff for next time. Nerds love those kinds of experiences. "Classic" American men tend to hate them, however, so they might not be the earliest of early adopters.
Jargon and esoteric concepts are draws for these sorts of folk, nerds and snerds, because they engender the potential to:
1. alienate others who do not know the "code" (half-joke here)
2. connect strongly with others who DO know the code
2.1. This forms a nucleation point for social activities (a MIAO phenomenon)
2.2. Forms a set of MIAOs for discussion, joke-making, building of narrative, lore, myth, history, etc.
In fact, that's probably why there ARE snerds. They like the social stickiness but can't handle the actual "being good at something that's hard" part (math, computers, foreign languages, music, etc.).
The idea of a "social nucleation point" is central to the principles of memetic engineering / analysis / deconstruction / hacking / etc.
One cool meme for doodz might be to "bring a buddy" to a birth. Just a thought (perhaps not a good one).
I thought of a marketing anecdote which might be relevant.
There's a legendary story about Wendy's Hamburgers and how they wanted to increase sales of their Double Cheeseburgers, since they felt them to not be selling well.
A marketing consulting company came back with the answer: put a TRIPLE Cheeseburger on the menu.
"Why should we do that?" wondered the Wendy's execs, "We already have poor sales of the DOUBLE Cheeseburger -- what good could a TRIPLE cheeseburger on top of that possibly do?"
The answer was that when they put the triple at the top of the menu, the double no longer looked like the "I'm the biggest fat-ass" thing to order, and double cheeseburger sales skyrocketed as a result, and, as expected, practically nobody ordered the triple.
Another example was when Carl Rove had to deal with yet another killer rumor during the "Baby Bush" (George W Bush) campaign. This time, the press had gotten wind of an alleged photograph of W snorting coke off of a bar someplace, or snorting coke off of the stomach of a half-naked young girl lying on a bar or other such PR nightmare. It was all anybody was talking about, the photo probably DID exist (it was never found, however, to my knowledge), it would not go away.
What did Carl Rove do? (WWCRD?)
Did he deny the photo's existence? No. He probably didn't even talk about it at all -- that would give it even MORE undesired visibility.
He leaked his own fake rumor that there was a EVEN WORSE photo of W dancing naked on a bar, drunk and stoned out of his mind.
The press immediately latched onto the idea of this new, non-existent photo, which was probably so outrageous in concept that they debated as to whether it even existed at all (of course it did not), they COMPLETELY forgot about the less-scandalous, probably real other photo, and eventually everything went away.
Why would I think of this?
I thought of what you were telling me about the placenta. It's kind of weird and gross, but it also is thought to have all kinds of magical properties, and a kind of strange beauty all its own if you look at it or smear it with paint or whatever in the right way.
Cows eat theirs, for one.
So, applying "Wendy's Triple Cheeseburger Principle" you can make up all kinds of "placenta-related" post-birth activities such as "placenta soup parties" after the birth, or "after-birth afterbirth" parties (or just "afterbirth parties") where the placenta is eaten by everybody who wants some or whatever, or tea is made of it somehow or whatever. This could be the EXTREME version, and even if nobody actually ever actually does it, certainly anything wimpy like just looking at the placenta, touching it, holding the bowl it's in, or whatever, is tame by comparison and therefore totally acceptable.
So if there are a few "placenta steak" or "triple placenta burgers" or "fried placenta" or "breaded placenta frittters" or "placenta gumbo" or "placenta chili" recipes out there, or "planting a plant / tree with your placenta" instructions, anything else placenta-related would be super tame and low-key by comparison.
The same goes for any of the other more "challenging" aspects of attending a birth (or anything). Set expectations such that they are way worse than anything that could ever possibly really happen, and nobody will be freaked out and everything becomes mainstream.
As soon as people start asking, "Aren't we going to EAT it?" at "after-birth" parties, you'll know your memetic engineering / marketing / PR project has succeeded. (^-^)