My 2nd DS has a dark blue spot that seems to have 'spread' up to the middle of his back (from top of botty) in the last couple of months. He is 8 months. Has this happened to anyone elses children? Also, my 1st DS still has his blue spot and he is 2+1/2. I was told this would probably disappear by his 1st birthday and this doesn't seem to be the case for either of my DS's. Not that I'm worried, just intrigued. Any comments?