Families migrate to the United States all the time and NEVER get separated from their children by the U.S. 

Never. 

If you are referring to people who choose to scoff at our borders and illegally invade our country in threatening numbers, and bring their children with them while doing so, those are NOT immigrants. 

Those are criminals caught committing a crime against the United States.  It is a serious problem for our country, that threatens our population and our economy. Frankly they are very lucky that they are dealt with so gently by this country.  Not so, in a lot of other places.  The U.S obviously has to do more to deter them from illegally invading our borders in the first place.

to present themselves at a port of entry and ask for asylum.  The US then determines if they can verify their qualifications as a refugee.  What is new is the deliberate use of taking children away as a means to deter people - even those who qualify under our laws - from seeking assistance.