Guides
Fifteen in-depth articles to understand infertility: medical definitions, how long conception takes, signs in women and men, PCOS, endometriosis, age, diet, stress, tobacco and alcohol, sperm quality and endocrine disruptors. These guides do not replace medical advice.
Infertility: definition, causes and when to see a doctor
What the word “infertility” actually covers, what the available figures show, how causes are distributed, and the point at which a medical consultation makes sense.
Read the guideHow long does it take to get pregnant?
The chance of conceiving per cycle, the timelines observed in the population, the weight of age, and one essential caveat: a longer-than-average wait is not a diagnosis.
Read the guideCauses of infertility in women
The main documented families of causes — ovulation disorders, tubal damage, endometriosis, uterine abnormalities — and the everyday exposures that can be acted on.
Read the guideCauses of infertility in men
Sperm production, motility and morphology, varicocele: the documented causes of male infertility, and the everyday exposures most often mentioned.
Read the guideEndocrine disruptors and fertility: the complete guide
What an endocrine disruptor is, how it is thought to act, what reference agencies say, and where you actually meet them in daily life.
Read the guideSigns that may point to infertility in women
Some gynaecological signs are worth discussing with a health professional. They are reasons to seek advice; on their own they do not establish a diagnosis.
Read the guideSigns that may point to infertility in men
Male infertility is usually silent. A few signs should nonetheless prompt a consultation — bearing in mind that only a semen analysis can document an abnormality.
Read the guidePCOS (polycystic ovary syndrome) and fertility
PCOS is the leading cause of infertility due to absent ovulation. It is also one of the situations where medical care most often changes the outcome.
Read the guideEndometriosis and fertility: what is the link?
Endometriosis is common and often associated with difficulty conceiving, without meaning infertility. Here is what is known about the mechanisms involved.
Read the guideFertility after 35: what the science says
Age is the best documented fertility factor. After 35, the odds per cycle decline more clearly — which does not mean infertility.
Read the guideDiet and fertility: what the science establishes
No food makes anyone fertile. Several associations between eating habits and fertility are documented, however, with varying levels of evidence.
Read the guideStress and fertility: what is the real link?
A link between stress and fertility does exist, but its direction is hard to establish. Here is what the data allow us to say, and what they do not.
Read the guideTobacco, alcohol and fertility: the demonstrated effects
Among modifiable factors, tobacco is the one whose effect is best established. Alcohol follows, with very clear data at high intake and more nuanced findings at low doses.
Read the guideDeclining sperm quality worldwide: what the studies show
A global decline in sperm concentration has been reported since the 1990s. The figures are striking and the scientific debate is real: here are both.
Read the guideHow to know if you are fertile: cycle, ovulation and signs to know
Understanding your cycle and spotting your fertile window helps target attempts. It says nothing about fertility itself, which only a medical assessment can document.
Read the guide
Including a factor does not mean it causes infertility: it is simply worth monitoring, depending on its level of evidence.
Content last updated: September 14, 2026