A: Texas calls prenuptial agreements "Premarital Agreements". These agreements, just like any other contract, can be challenged in court. A challenge to the agreement does not mean it will be found invalid, however. Surviving a challenge to the premarital agreement is primarily accomplished all the way back to when the agreement is drafted and executed. There are requirements or prohibitions for the agreement terms to be valid, which are too numerous to list here, but can be found in the Texas Family Code, chapter 4. In Texas, no consideration is required, but the Agreement must be in writing, and signed by both parties. It must be free from fraud and duress, and entered into voluntarily. It cannot be unconscionable, and the parties must provide a fair and reasonable disclosure of the property and financial obligations (unless waived). Enforcement of a premarital agreement falls under the Texas Family Code 4.006.
Additionally, any provision that would adversely affect the support of children is going to be prohibited. Conservatorship and possession/access (custody and visitation) will always be determined by the Court under the best interest of the children standard, regardless of what may have been put into the agreement.
The best way to survive a challenge is to hire a competent attorney to draft the agreement, ensure the agreement complies with the Texas Family Code, provide a fair and reasonable disclosure from both parties, both parties being represented by their own attorney when entering into the agreement, and ensuring the agreement is available for review far in advance of the wedding date.