The couple - who already have a 14-month-old biological daughter, Shiloh, and three adopted children, six-year-old Cambodian boy Maddox, Vietnamese son Pax Thien, three, and two-year-old Ethiopian girl Zahara - are said to have decided to start trying for another child.
A source said: "They've decided the time is right to try for another baby. Brad is crossing his fingers that it will be a boy."
To give themselves the best possible chance of conceiving, Brad, 43, has been reading a number of health books and is cooking Angelina, 32, fertility boosting meals.
Last week, it was reported that Angelina and Brad are planning to adopt another child from Ethiopia, reports Life Style Extra.
The couple are said to believe another baby will help Zahara feel more secure within the family, because of shared African heritage.
A source close to the couple revealed: "Angelina feels that while Shiloh will see the family resemblances between her and her natural parents, and Maddox and Pax will have a connection through their birthplaces, Zahara has no such close-knit bond. They hope by finding a sibling for her, Zahara will feel more comfortable in her own skin."
The couple are said to be planning to visit Ethiopia 's Wide Horizons agency, the same place that introduced them to Zahara, in November, reports Post Chronicle.