Your age, your weight, your diet - there are plenty of things that we know affect our fertility as women.

Sadly, some factors are a little less predictable and preventible - underlying medical conditions and genetics play a role in how fertile we are but are unfortunately out of our control. Now it's thought that even the age our own mums had us at could be a factor in how easy it is for us to get pregnant. A new study of over 43,000 women at McGill University in Quebec has found that a significant number of women without children were born to older mothers. Almost one in five of the women studied whose mums were over 30 when they were born did not have children, it found. The researchers couldn't tell whether this was by choice or due to fertility problems. "We had no knowledge of whether childlessness was intentional," they said in notes, but added that "the association with childlessness was highly consistent." This conclusion echoes what other research concluded over 10 years ago. A 2006 study found that women attending a fertility clinic in Atlanta were more likely to conceive if they themselves had been born to younger mums. The findings from this study suggested that the closer a woman is to menopause when she gives birth, the more likely it is that her daughter will have trouble conceiving as an adult.

"When we are treating patients close to the age of 40, we are helping them get babies but, at the same time, these children will have a higher risk of becoming infertility patients," Peter Nagy of Reproductive Biology Associates in Atlanta said at the time.