If you and your spouse wish to have babies, you’d better not delay the time of conceiving too much, at least that is what a team of French researchers suggests.

To be more specific, they found that couples trying to conceive when the man is over 40 will have more difficulty in doing that compared to situations when he is younger.

For the study, researchers at France’s Eylau Centre for Assisted Reproduction led by Dr. Stephanie Bellos monitored 21.239 cases of intrauterine inseminations (IUI) in more than 12,000 couples between January 2002 and December 2006.

Intrauterine insemination is a type of artificial insemination in which the sperm are washed or spun in a centrifuge to separate them from the seminal fluid and then inserted directly into the uterus when the woman is ovulating. Intrauterine insemination is given to couples where the woman has no fertility problems. The method is less invasive than in vitro fertilization.

The researchers further examined the quality of the sperm (their ability to move and swim and their size shape) and then tracked pregnancy, miscarriage and delivery rates.

According to the findings, the maternal age was closely associated with a decrease in the pregnancy rate – 8.9 percent in women over 35 years, compared with 14.5 percent in younger women, as well as a higher miscarriage rate.

However, what was the most surprising was that fact that, apparently, not only the mother’s age can be a decisive factor in conceiving a baby. More exactly, “the age of the father was [also] important in the rate of pregnancy, with a negative effect for men over 40,” Dr. Belloc said, adding, “even more surprising, the proportion of miscarriages went up as well.”

The study showed that the age of men led to decreases in the pregnancy rate, from 12.3 percent with fathers 30 years of age or younger, to 9.3 percent in fathers older than 45 years of age. The percentages were almost double when it came to the rates of miscarriages from 13.7 percent to 32.4 percent.

The rates clearly show that gynecologists “must also focus on paternal age and give this information to the couple” and not only on the maternal age, as they have done it before.

Dr. Belloc presented the study to the European Society of Human Reproduction and Embryology (ESHRE) conference in Barcelona on which occasion she said the research “has important implications for couples wanting to start a family.”

This is not the first time a study suggests that the age of men is important when trying to conceive, according Dr. Alan Pacey, a fertility expert at Sheffield University and secretary of the British Fertility Society. He told the BBC that “previous studies of couples trying to conceive naturally or undergoing IVF have shown that men over the age of about 40 are less fertile than younger men. Moreover, if they do achieve a pregnancy their partners are more likely to miscarry.”

Therefore, Drl. Belloc’s study is a clear message that men “aren’t excused from reproductive ageing.”

Of course, the findings do not apply to all men over the age of 40, as there are cases of successful pregnancies even after that age. However, couples should be more aware of the fact that having a child at earlier ages is safer for both parents and the child.