There are a few modifications to Secure Flight that will affect many passengers. Additional data is required for travelers to the US (this applies even to existing bookings)
For travel from November 1 and onwards, passengers must include their date of birth and gender in addition to their full name on all bookings no later than 72 hours before their scheduled departure. The additional date requirements applies to all international flights to and from the United States as well as to flights within the US, regardless of when the booking was made. If you have not provided the necessary Secure Flight Passenger Data, you may be refused boarding by the US authorities.
Secure Flight and TSA Airport Security Videos are both worth checking out for more info about rules and regulations.