I never ever gave a thought to due dates, months to avoid, "best" time of the year to have a baby, but I can understand sort of understand why people do it.
Well, to be honest, I never gave much thought to becoming pregnant or having an actual baby, so when I found out I was pregnant it was quite enough shock let alone wondering whether it was a good due date or not.
I don't think vain is quite the right word for it- each to their own, everyone has to do the right thing for them and their partner.
We have been TTC since my missed miscarriage last summer- I would never purposely miss a month of TTC to avoid a certain birthday!
Each month counts and you just never know.
As you can tell, I would just be grateful to have another successful pregnancy, really couldn't give a flying one about which month/time of the year it will be in!
I've also just decided that it's all pot luck now- just because you decided to start TTC next month or whatever, doesn't mean it's going to happen any time soon or that you'll even make it past the dating scan.
But that's just me, my outlook is very much shaped by recent bad experiences.