I would begin by visiting the EEOC website, as well as the Texas Workforce Commission, for the employer-side resources. You ought to stay away from disability issues, pregnancy issues, and related types of matters. This is pre-offer. After an offer is made, different rules apply. It also depends upon how big your company is. Different laws apply to different size employers. The EEOC, Department of Labor, and Texas Workforce Commission all have resources to guide you on this. I also suggest you meet with a lawyer. Best of luck.