If science has to answer then “In Vitro Fertilization" is said to provide a better chance to give birth to twins. Not only in case of the celebrity community but even the 'not so famous' couple have been blessed with the chance. Since 1980s, it is said that the chances of twins has been up by 75%.
In Vitro Fertilization is a technology that provide a opportunity to women to have a baby. This assisted reproduction helps them to get what they wished from a long time. Since fertilization is uncertain, the doctors wouldn't want to take chances and implant two or three fertilized eggs so that at least one baby gets successfully developed. In most cases, the number of eggs implanted may all get fertilized and develop into two, four or more babies.
Another reason for most celebs having twins is may be because they conceive after 35. The age factor also is said to play some role in the birth of twins. Which is why most women plan to start family or get settled after 30. The trend has been on rise since few years.
Another thing that comes under notice is that the celebs mostly have fraternal twins (twins born from separate eggs and separate sperms) where the chances of the two looking similar is rare. Identical twins are produced by a single egg and fertized by a single sperm. The egg splits into two identical halves resulting in babies looking exactly same. Neither the age nor any factor has anything to do with the identical births.
If having identical twins run in your families, there are some chances that you may have the same. Many women also state that they gave birth to twin babies even when they were well within thirties, didn't have family history or IVF. Afterall, there are things that even science can't explain.
Celebs who recently had twins include Julia Roberts, Jennifer Lopez, Brooke Muller (Charlie Sheen"s girlfriend), Mariah Carey, Sarah Jessica Parker, Angelina Jolie, Julia Roberts and many more.
Famous Bollywood director Farah Khan had triplets while another director Kiran Rao (Aamir Khan's Wife) had a baby through IVF. Stars always maintain secrecy with respect to their relationships and pregnancy so it is hard to determine who went for what unless they say it openly.