Question: how likely is it for you to get twins if your grandfather is a twin

Gill Harrison answered on 27 Jan 2019:

I don’t know the exact figures, but it will depend on many factors.

Twins may run in families if it’s a genetic link, but in other cases it can be linked to the environment or other factors. Twins are more common if the mum has had fertility treatment for example.
Twins that come from the one egg that splits during early development (monozygotic) are not thought to be genetic, but there is still some doubt about whether it can be in some cases.

Twins that come from two eggs fertilised during the same cycle (dizygotic) are more likely to run in families. There have been studies that have found links between ‘hyperovulation’ (when someone releases more than one egg per monthly cycle) and some genes, so they do think there might be a link. It’s possible that if your grandfather is a non-identical twin that you could get twins.

When i’m scanning we do get quite a lot of women who are not surprised they are told they’ve got twins, if one of their grandparents was a twin.