A guest writes: "Is giving birth to twins hereditary ? Or does it just increase your chances? My partner is a twin (not identical). My mother is a twin (identical). Also on fathers side my Great Grandmother gave birth to twins. (identical) I was just wondering as no one else in the family has giving birth to twins except for a cousin of my fathers. Is it a myth?"

Ahhh, the great "twin gene" question. Do you have to have a family history to have twins? Is twinning hereditary?

The answer is ... sometimes. Some twins -- fraternal or dizygotic twins only -- are the result of hyperovulation, a female tendency to release multiple eggs during ovulation. If two -- or three or more -- eggs are fertilized and implant, the result is twins or multiples. Hyperovulation can be a genetic tendency, so if a mother has the gene for it, her daughter might also. In that sense, it can be said that twins run in the family, but on the mother's side only. Fathers don't ovulate, so they don't impact twinning in this scenario.

Not all dizygotic twins are due to family history. Other factors besides genetics can cause hyperovulation, such as fertility treatments, birth control pills, breastfeeding, advanced maternal age, and even dairy products.

A genetic impact on monozygotic (identical) twinning has never been identified. That's not to say that clusters of identical twins don't repeat within families. However, you can't credit it to -- or blame it on -- genetics. Call it fate or coincidence, or just plain good luck.

So let's look back to the original question. Is this message forum guest likely to have twins? What do you think? Stop by the message forum and share your input.

More resources:
• The Twin Gene: Do Twins Run in Families?
• How to Have Twins
• Identical or Fraternal? Understanding Zygosity

I like to read. Call me enthusiastic, avid, or voracious, but feeding my hunger for books has cost me a pretty penny over the years. The library is great, but unfortunately you have to give them their books back eventually. My twins aren't quite as eager of readers as I am, but they have always liked books, and thus our house is full of stocked shelves.

A few years ago, I found a great way to keep myself supplied with books without spending a lot of money. It also allows me to clear out the books that I no longer want. Paperbackswap.com is a free web site that allows members to recycle used books. Despite its name, the swapping is not limited to paperbacks, but includes all forms of books, including audiobooks on CD or cassette. As a requirement join, you're asked to post ten books that you'd like to swap with other members. This gives you the ability to request books from other members. Requesting a book is free! However, in order to earn credits to request books, you're required to post and send books to other members, and you'll incur the cost of postage for sending the books. The site provides a convenient mailing label and even offers you the option to pay for postage online. It costs $2-$3 to mail a book, depending on postal rates and extra services.

With over 3 million books posted into the system, and new books being posted all the time, Paperbackswap.com is a wonderful place to obtain the books that you and your family want to read. Their are books in every topic and genre, from bestellers to textbooks, from cookbooks to picture books. I've often relied on it to acquire books in duplicate when both my twins wanted their own copy of an item. I've also used it extensively to clear out my bookshelves, sending out my old books to readers far and wide and making room for new things to read.

You can also save money on music and movies at Paperbackswap.com's sister sites: SwapaCD.com and SwapaDVD.com.

More Thrifty Thursday Tips from About.com's Parenting & Family Channel Guides:

• Cheap Birthday Gifts That Promote Fitness
• Getting Out of Debt and Staying Out of Debt
• Affordable Infant Car Seats
• Saving for College at the Grocery Store
• Recycle Old Jeans
• Plan a Fun Tween Sleepover Party
• How Does 50% Off Your Hotel Stay Sound to You?

Play ball! Ryder Jay and Korgan Kyle are five month old fraternal twins.
• Share your thoughts, opinions and advice in the comments section.
• More Worldless Wednesday Posts on About.com.
• More pictures of baby brothers: Infant Twin Boys Photo Gallery
• Index of All Photo Galleries

A recent visit with my nephews made me realize just how different boys and girls can be. Having only been a mother to girls, I was baffled by some of the ways of boys. They play differently, think differently and act differently. Although I know that there are a lot of things that I am missing by not having a son, I thoroughly enjoy having daughters. I was definitely cut out to be a mom of girls.

What would make your family perfect? What if you could choose to have boy twins, girl twins or one of each? Even if you could choose, should you? Find out if gender selection really works, and how it impacts multiple birth.