Happy Birthday, George! The little prince loves dogs, hates bath time, and wakes his dad at 4 a.m. Rounding his first birthday, Prince George is growing into a spirited toddler as his parents prepare to make him a big brother. This week's issue of PEOPLE takes a look inside how Prince William and Princess Kate, both 32, are raising their firstborn - and getting ready for baby No. 2. The Palace won't comment on the near-daily but ever-changing rumors that Kate is pregnant (with a girl! with twins! with twin girls!). A source close to the couple confirms they plan to give George a sibling not too long from now, but "they don't say when." Plus: George's "Baby Book," which chronicles his first year in photos.

More stories are featured in the new issue of PEOPLE, on newsstands everywhere now.

*Also In This Week's People:*
Exclusive: The Biggest Loser's Jillian Michaels: Why I Had To Leave
Exclusive Prison Interview With Pamela Smart, The To Die For Killer
Ryan Gosling & Eva Mendes: How They Hid Their Big Baby Secret