According to the article:
However, Senate Bill 328, which passed in the last Texas legislative session, means that anyone involved in a crash, whether they're suspected of drunk driving or not and where there's bodily injury, severe or not, or has a child in their car, or previous D.W.I. convictions, will have blood drawn automatically within a matter of minutes.Here is a link to the text.
I couldn't find the part about having a child in the car. The kids are playing in the room so I may just be missing it. However, since anyone with a minor bruise or cut will frequently go to the hospital or doctor just to make sure there isn't something serious you can bet that most of the time if the police show up at an accident then all drivers will be giving up their DNA.
What is wrong with Texas these days?