I have two daughters - 3 and a half and 2 months. My SIL also has two children of roughly the same age (dd and ds) and lives the other end of the country. The PIL spend every other christmas with SIL and her two children and her husband's family at their house and don't see our children until the week after they come back from there.
I know that thay think more of their daughter's kids than mine and I raised all of this with them last year after a falling out. They denied this of course, but after having my second dd, the comment from FIL to my husband was 'another girl, never mind' to which my dh replied that he was delighted and didn't want a son (which they did).
I probably am being unreasonable, but why do their children get to see their gp every christmas and mine only every other? FIL made a big thing when I was pg about being my dd's only grandad - my dad died when I was 19-yet he can't follow this through and constantly talks and gushes about his other gd and calls my gd by her name. I do think that my dd senses this as she never goes out of her way to be with grandad and goes straight to MIL this is especially the case when the other gd is there.
My SIL's second child is a DS - the only boy and can't do any wrong - wonderchild, so my baby girl has no chance. The last few weeks he hasn't even held her yet again, gushes about Gs all the time. He also keeps getting my new dd's name wrong.
The whole situation pisses me right off. I know all about the daughter-parents relationship, but do think that there is a lot of favouritism on their part!