Can you post a picture? There are several plants which go by the common name 'Stinging Nettle'. Knowing which one you have would help people come up with suggestions.

Whatever it is, though, if you have children I'd use repeated mechanical methods rather than herbicides.

It´s a sign that your ground is nitrogen-rich. I´d go for a mechanical approach (pull or mow regularly for a while to weaken them), then add competing nitrogen-loving plants with large leaves and more substantial growth.

"It´s a sign that your ground is nitrogen-rich." That's true if we are talking about Urtica dioica but until we can establish which species is being referred to it is hard to say what it is a sign of. I know what Stinging Nettle means to me but different plants are given the same common epithet in different places. Plants known as nettle But whatever it is I agree that he mechanical route is the safest.

As far I know "stinging nettles" refer in Texas commonly to Urtica dioica, in contrast to "bull nettles" or "horse nettles". But, you are right, a picture would be good to be sure.

If it's an area where your children are playing, I'm with Floral that I'd avoid herbicides or at the very least read the labels extremely carefully before using. Some herbicides are relatively long-lived or break down into substances that last quite a while and may include substances that can cause harm, particularly to kids' developing systems. I'd not want to take chances on my kids . . .

Mowing and pulling with proper protection, flame weeders, or tilling along with planting alternative plants that will compete with the nettles may be sufficient - it's certainly where I would start.