Check out what the insurance changes/benefits would be, especially with a baby that's about to be born.
My gut says to make the move. If you are worth 50% more, then why wasn't your current employer paying that much more? My gut, fwiw, is that eventually your current employer, if they can match it, will start to resent paying you so much more for a job you were doing for much, much less. I could be wrong, though. But seriously, check out insurance changes and how that will change your bottom line. Wouldn't be so much of an issue without a baby on the way, though.
But good job, man, with getting a great offer and counter offer!