Splice was written by director Vincenzo Natali and screenwriters Doug Taylor and Antoinette Terry Bryant. The script was originally meant to follow up Natali's Cube (1997), but the budget and restricted technology hindered the project. In 2007, the project entered active development as a 75% Canadian and 25% French co-production, receiving a budget of $26 million. The director described the film: "Splice is very much about our genetic future and the way science is catching up with much of the fiction out there. "[This] is a serious film and an emotional one. And there's sex... Very unconventional sex. The centerpiece of the movie is a creature which goes through a dramatic evolutionary process. The goal is to create something shocking but also very subtle and completely believable."
A brief interview with Natali here.