It worked for me.

I was overseas (without DH!) up until Day 15 of my cycle, so obviously no BD-ing. I noticed lots of EWCM whilst away and pretty much ruled the month out all together. The only time we BD'd that cycle was the night of Day 15 and I had Aidan 9 months later! I wanted a boy so it worked perfectly for us, not that I knew I was doing the right thing at the time.