When I looked at the attempts forum this is what I saw:
For the women ttc'ing for a girl:
The women that tried under a FULL moon phase conceived more girls than boys.
The women that tried under a NEW moon phase also conceived more girls than boys.
To me this shows that moon phases don't really matter much at all, all of the other factors that these women were doing gave them a better chance at conceving a girl, so regardless of the moon phase they were O'ing in, more girls were conceived.
I really wouldn't worry about the moon phases, I think it is so far down the list of things to do when ttc'ing for a girl that it is not something you should concern yourself with at all. You should ttc when you want to ttc.
That being said, I do think that you should START trying in the right season. This is something you can control...if you end up not conceiving during the right season, then I think it's ok to keep on ttc'ing,...but you should start in the right season and not worry about the moon phase...just load up on - ions