Hey there, what Dawn said :)
Also, we had another forum member in the past (BusyMom) who had LIS, but I'm not sure how long after childbirth that was (sorry). You can find some of her threads here and they might be worth a gander. If I recall correctly, she did really well after LIS and was cured completely:
http://anal-fissure.org/st/busymomI'm obviously not a mom, but for what it's worth, I had LIS a little over a year ago, and wife and I had twins (one normal and one with cerebral palsy) 21 months ago. My gut feel would be to go with your female CRS for the following reasons:
1. She's female. I don't mean for this to be sexist. But I do feel that women, whether they have children or not, will likely have a better idea of what it's like post-partum than men. I know it was tough for my wife (she quit her job so she could care for the kids), and recovering from surgery would definitely add to the stress and craziness of this busy time. For example, you'll need to take plenty of soaks in the tub, which probably won't be too convenient.
2. Your butt will be uncomfortable after LIS. To what extent and for how long depends, but there will definitely be some level of discomfort. Breastfeeding while sitting upright won't feel very good (if you can manage it at all), and even if you "sideline" to feed, that can still put some pressure on butt areas that are better off resting comfortably.
3. LIS recovery times can vary widely. Some people recover in days to weeks. Some take up to a year or more in rare cases. Many surgeons will tell you that you'll be right back on your feet a week or less later, but please don't blindly take that at face value. Many of us have found out the hard way that it's just not always so. It's true that it can happen, but I would consider this the best case rather than the norm.
Now, the last argument can actually go both ways. Since LIS recovery times vary so wildly, it does make the surgery tough to plan. Plus, there's no guarantee that the kiddo will be any easier to take care of 6 months down the line. Still, I personally think it would be nicer to have some time to settle down after giving birth before going into LIS. Even though I'm not the primary caretaker for my kids (I'm no deadbeat either but truthfully my wife handles the vast bulk of the kid work), I still put off LIS until the situation with my kids was a bit more stable.
Finally, here's one bit of food for thought IMO: is there a time when you have the most access to help with the kid(s)? Maybe a parent or in-law? If so, that would be a major decision point for me. I would give preference to whenever you have someone to take care of the kids while you recover, regardless of all other variables. Even in the best cases, you WILL need to take it easy for a bit after LIS, so whenever you have help with the family is the best time IMO. If that's before you plan on stopping breastfeeding, you can still pump breast milk while your helper feeds it to your baby.
Take this with a huge grain of salt, of course, since I'm just a dude :) We have plenty of mothers on this board and I'm sure they'll chime in soon enough. If you don't get that many responses here, please feel free to post further down in the "Considering surgery or already had it?" section since that subforum tends to get the most traffic, and your question is indeed about surgery.
Oh and welcome to the boards ... and sorry to have to be here :(