Complex sentence: On October 1,2005, Shriver gave birth to twins, Kate and Sam, and was also stepmother to Lazenby's daughter, Melanie Lazenby, from his previous marriage.
Split into simpler sentences: On October 1,2005, Shriver gave birth to twins, Kate and Sam. She is also a stepmother to George's daughter, Melanie Lazenby, from his previous marriage.