HOUSTON — For a small person who had surgery before he was even born, and who’d just spent an hour and a half squeezing through a tight space that clamped down on his head every few minutes, Baby Boy Royer was showing a feisty spirit.

He arrived pink and screaming on Friday at 5:35 a.m., two days before his official due date, weighing 8 pounds 8 ounces, and almost 20 inches long.

Within moments of his birth at Texas Children’s Hospital, he did what his parents and doctors had eagerly hoped to see: He moved his legs and feet, a sign that the operation may have prevented damage to the spinal nerves needed for walking.

Indeed, placed on his belly, he managed to pull a knee underneath himself and push off, as if he intended to crawl away from the nurses who were trying to swaddle him.