Gay marriage

The Supreme Court is going to rule on the same-sex marriage case and while I am not opposed to Gay marriage, I can foresee some possible problems. At one time in my career I was involved in estate planning. When the first spouse dies proper planning will allow most of the estate to pass to the surviving spouse without much tax and this same planning can reduce the tax when the second spouse dies but there will be tax as the estate passes to the heirs. I can see a time in the future where a man dies and his wife marries his son and then when she dies the estate passes to the son without any tax. Thus the estate passed to the next generation without tax. This is not legal now but if the rule is that marriage between consenting adults is OK, will marriage between relatives be next. This also leaves open the door for polygamy. These things are not likely but I mention them only as possibilities because so often the government fails to see the unintended consequences of good intentions.