Since it is relatively unusual to be pregnant with twins, I have had quite a lot of people asking me questions about being pregnant with twins. Let me share them with you! :)
The most common question asked by far, is, whether my husband or I have any family history of twins. Well, in fact, I do. My auntie (my mother's sister) has twins (the twins are my cousins). So then most people would comment that it must be because of that that I'm having twins.
According to my gynae, having a family history of twins does increase the chances of having twins (especially fraternal twins), but that the twins genes is usually passed down the "maternal line". In other words, it is more crucial for the mother's side of the family to have the twins genes, rather than the father side - coz it is passed down the mother's side.
However, reading about twins online, has turned up a fact which I found fascinating. Wikipedia has an informative article on twins which is not too long and overly scientific . In it, it is mentioned that the likelihood of a single fertilisation resulting in mono-zygotic (identical) twins appears to be a random event, not a hereditary trait, an anomaly that occurs in birthing at a rate of about three in every 1000 deliveries worldwide. Go read the article for more details on facts about twinning!