This question, of course, was famously raised by George Costanza in Seinfeld (→ Youtube clip). But what does science say? What’s the percentage of individuals with two X chromosomes who know about shrinkage?
Know about what?
Did you mean shrinkwrap?
Please provide a context where the subject would ever come up with a person you are not already intimate with.
i.e., penile shrinkage due to cold.
A brief one-sentence description of what you’re talking about instead of saying “see link” is good board etiquette.
And, while we are on the subject of things that guys know that girls do not and vice versa:
Do girls *really *mark their calendars on the day their period starts? I’ve run across references to this practice in fiction, where the the guy notes that the mark is missing for the last month or two…
Is this really a thing? I suppose I could ask my wife, but… no.
I got a vasectomy a couple of weeks ago. The nurse came in the room and aimed a large fan at me. The doctor walked in and said “Turn off the fan or we’ll be dealing with shrinkage.” Nurse complained that she was having hot flashes and had to have the fan on. Doctor told her to point it elsewhere, but not on the patient’s (my) naked testicles.
Some women do. If I had to make a guess, I’d say that like 25% probably do. The number would go way up for women who are trying to conceive, or practicing “the rhythm method”.
Yes, I think most women know about shrinkage. It’s a fairly well joked about phenomenon. Like, it was in Seinfeld, for goodness’ sakes. Wimminfolk watch Seinfeld.
BrotherCadfael, we used to. Now we have apps for that.
Well, a doctor / patient relationship is pretty intimate. I know the doctor likes to have as much room to work as he can get, so a retracted scrotum would make his job that much more difficult.
Not that I’m aware of. I guess if they were *trying *to get pregnant they might chart it. Also, when things in that area start to get irregular one might make note but in general women are pretty in tune with their bodies without having to mark the days on a calendar.
Also, though I’m not in the habit of getting into physical altercations, when I *do *get into a hair pulling, hissy kitty slap fight with another chick we almost never end up making out 
I assumed that only those who “got” the Seinfeld reference would even bother. I have to admit, though, that my post was mundane and pointless.
Marcus Licus (to Eunuch): How many times have I told you not to fan the girls when they’re wet! But you’ll never learn. You’ll be a eunuch all your life!
… —(a Funny Thing Happened on the Way to the Forum)
I mark my calendar - to make sure I have supplies on me as it gets near. For many years I was irregular and wanted to see how out of whack I was. Now that I’m older I rarely get PMS as an indicator and it tends to start suddenly.
Suspect husband has my cycle on his own calendar. But he calendars everything in his life.
And yes, certainly know about shrinkage.
It really depends. I am regular as clockwork and thus never mark it. I mostly can’t even tell you what day I started last time, and when my gynecologist asks me I always have to think about it. If it was irregular I would clock it, and when I was a teen and unexpected things happened I always clocked it.
I do know about shrinkage. I even know about show-ers and grow-ers.
Even before Seinfeld, I remember learning about it from a male friend in about 9th grade or so. I don’t know that we’ve ever had a conversation about it, but I am pretty sure all of my female friends know about it- we are in our 30s though, so were around for Seinfeld. I don’t think we think about it very much.
And I have tracked my cycle off and on for years. Sometimes I’ll get too busy or what have you, but as a general rule I put a little circle on the calendar. It’s helpful to know for a variety of reasons already mentioned, and you get asked at the doctor even if you’ve gone for an unrelated issue.
Also an episode of X-Files; half a dozen people went to the Antarctic and had to drop trou to see whether or not they had been infested by the alien worms, and Mulder said “Remember, we came to Antarctica…”
YMMdefininitelyV. Keeping track of the start of each period – whether by a mark on a calendar, an app, whatever – is pretty common.* Search your app store of choice to see how many are available.
Most women I know who keep track fall into three categories:
[ul]
[li]Want to be sure they’re not pregnant.[/li]
[li] Have really, really irregular cycles (data collecting to either mayyybe find some sort of pattern or anything that might help figure out why, or as detailed records to document they know what they’re talking about).**[/li]
[li] Are very detailed and data-driven in general and keep track of tons of other things, too.[/li][/ul]
- I don’t, so I don’t personally have a dog in this fight.
** There are, sadly, a lot of crappy gynos who can be really dismissive of concerns like this and/or assume that it’s not really all that irregular, they’re just worrying over nothing.
Oh, and to respond to the actual OP: Yeah, in general, chicks know.
Female here.
I know about shrinkage, mainly from Seinfeld and other pop culture references.
My periods have always been irregular, so I have always tracked them. Since I still use a paper check register to balance my checkbook, and they always have a tiny three-year calendar on the back, I use that.