Fertility beliefs put to the test, starting with the fact that men play a part in about half of couples’ struggles

Key takeaways

• The World Health Organization estimated in 2023 that about 1 in 6 people worldwide will face infertility at some point in their lives².
• Men are part of the picture in about half of couples who have trouble conceiving, according to NIH’s child-health institute⁵.
• A review of 14 studies with 3,583 women found that anxiety or depression before fertility treatment didn’t lower the chance of pregnancy¹.
• Frozen eggs carry no guarantee: in one study, each thawed egg from a woman under 30 had about a 7% chance of becoming a baby¹⁰.
• In an NIH trial of 2,370 couples, folic acid and zinc pills for men didn’t raise live births, 34% versus 35% on placebo⁶.

If you’ve been trying for a baby for a while, you’ve probably heard it. Just relax. It’ll happen when you stop trying so hard.

People usually mean it kindly, but it can still land like blame.

In 2011, a research team writing in the BMJ, a leading medical journal, put that advice to the test. They pooled 14 studies that measured anxiety or depression in 3,583 women before a cycle of fertility treatment, then tracked who became pregnant¹.

Women who felt more distressed got pregnant just as often as calmer women¹. The authors wrote that their findings should reassure women and their doctors¹.

Many fertility beliefs work the same way. They sound like common sense, they put the weight on one person, and the evidence doesn’t back them.

This article checks the most common ones against the best data we could find. If you’re in the middle of trying, we hope it lifts some weight rather than adding to it.

Infertility is common, and it isn’t a personal failing

In April 2023, the World Health Organization (WHO) estimated that 17.5% of adults, or about one person in six, live through infertility at some point². Lifetime rates were 17.8% in high-income countries and 16.5% in low- and middle-income ones, with little difference by region².

WHO counts infertility as a disease that can affect a man’s or a woman’s reproductive system. The marker is no pregnancy after at least 12 months of regular sex without birth control². “Infertility is a medical condition. A medical diagnosis,” Pascale Allotey, WHO’s director of sexual and reproductive health and research, said at a WHO briefing².

U.S. numbers tell a similar story. Among married women aged 15 to 49 who have never given birth, about 1 in 5 can’t get pregnant after a year of trying, the CDC says³. About 1 in 4 in that group have trouble getting pregnant or carrying a pregnancy to term³.

Across all U.S. women aged 15 to 49, 13.4%, or about 9.7 million, had that broader kind of difficulty in 2015 to 2019, according to the National Survey of Family Growth, a federal survey⁴.

Numbers shift with the definition used. The CDC notes that survey definitions don’t decide when you should seek care³.

Belief: infertility is mostly a woman’s problem

It isn’t. Male factor subfertility plays a role in about half of couples who struggle to conceive, according to the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), part of NIH⁵. The cause is often unknown⁵.

The federal survey asked men, too. In 2015 to 2019, 11.4% of American men aged 15 to 49 had some form of infertility, by the survey’s measure⁴. The share rose with age, from 7.8% at ages 15 to 24 to 14.3% at 45 to 49⁴. The survey notes that men’s and women’s measures can’t be compared directly⁴.

The CDC lists factors that can harm male fertility. They include obesity, smoking, heavy drinking or drug use, injury to the testicles, frequent heat on the testicles, radiation, some medicines and toxins³.

Testosterone is on that list³. Prescribed testosterone can shut down sperm production, as our companion article on testosterone explains.

One reassuring note from the CDC: a semen test that comes back a little off isn’t proof that a man can’t father a child³.

So if you’re the woman in a couple and you’ve been carrying the worry alone, the science says it may not be yours alone to carry. Ask that both partners be part of any evaluation.

Are sperm counts really crashing?

One major estimate comes from a 2022 review. Hagai Levine of Hebrew University, Shanna Swan of Mount Sinai and colleagues pooled 223 studies of samples collected from 1973 to 2018⁷⁸.

Among men not selected for fertility, average sperm concentration fell 51.6% over those years, about 1.16% a year⁷. After 2000, the yearly drop sped up to 2.64%⁷. The study didn’t look at causes, though its authors point to possible environmental and lifestyle factors⁸.

Not everyone reads the data the same way. In a paper published online in 2021 in the journal Human Fertility, a group of critics argued that healthy sperm counts span a wide range⁹. Making sense of trends, they wrote, means accounting for each man’s life history and surroundings⁹. They also pointed to weaknesses and inconsistencies in the assumptions behind the decline argument⁹.

What does this mean for you? A worldwide average can’t tell you about one man’s sperm, but a semen analysis can.

Belief: stress is why you’re not pregnant

The 2011 BMJ review is the clearest answer we found. Across 14 studies, women’s distress before treatment had no link to whether the treatment worked¹. The authors did flag moderate publication bias, meaning some studies may never have been published¹.

There is a kernel of truth. The CDC says physical or emotional stress severe enough to stop periods can affect fertility³. That condition, functional hypothalamic amenorrhea, can also come from heavy exercise or weight loss³.

If your periods have stopped because of under-eating or over-exercise, the National Alliance for Eating Disorders runs a free weekday helpline at 1-866-662-1235.

Stress also shows up in the bedroom. The American Society for Reproductive Medicine (ASRM) says the pressure of trying can lower sexual satisfaction and how often couples have sex. Rigid scheduling around ovulation tests can make that worse¹².

So rest, walks, prayer, therapy or time outside are worth doing. Do them because you deserve care, not as a fertility test you can fail.

Infertility can bring real grief. If the weight of it feels like too much, or you have thoughts of harming yourself, call or text 988 to reach the 988 Suicide & Crisis Lifeline.

Belief: age matters only for women, and IVF can make up for it

Age matters for women most. After 30, the odds of a woman giving birth fall quickly year by year, mainly because egg quality declines, the CDC says³.

ASRM puts it another way: fertility at 40 is roughly half of what it is in the late 20s and early 30s¹². Still, about 80% of couples conceive within their first six months of trying, ASRM notes¹².

The federal survey shows the age pattern clearly. Among married women who had never given birth, difficulty getting or staying pregnant rose from 16.2% at ages 25 to 29 to 46.0% at ages 45 to 49⁴.

Men’s age matters less, but it isn’t zero. ASRM says semen measures decline after 35, though male fertility isn’t much affected before about 50¹². The CDC says couples with a male partner 40 or older are more likely to report trouble conceiving³.

IVF helps many people, but it can’t erase age. In 2021, U.S. clinics reported 413,776 assisted-reproduction cycles and 97,128 babies born¹⁴.

Here is the share of planned egg retrievals, using a woman’s own eggs, that led to a live birth¹⁴:

Age	Live birth per planned retrieval
Under 35	50.7%
35 to 37	36.3%
38 to 40	23.3%
Over 40	7.9%

By our math, that’s about 1 in 2 under 35, compared with about 1 in 13 over 40.

Belief: freezing your eggs guarantees a baby later

Egg freezing can widen your options, but it isn’t a guarantee.

ASRM’s 2021 guideline says there’s very little evidence for predicting a live birth after planned egg freezing¹⁰. It flags a risk that women will wrongly feel a future pregnancy is locked in and put off trying¹⁰. Only a small share of women have returned to use their frozen eggs so far¹⁰.

One study cited in the guideline followed what happened to thawed eggs¹⁰:

• Each egg from a woman under 30 had about a 7.4% chance of becoming a baby.
• The chance was 7.0% at ages 30 to 34, 6.5% at 35 to 37, and 5.2% at 38 and older.
• For a 70% chance of one baby, the authors estimated 14 mature eggs at ages 30 to 34, 15 at 35 to 37 and 26 at 38 to 40.

A 2017 model from Brigham and Women’s Hospital in Boston gives similar odds¹¹. With 20 mature eggs, the chance of at least one baby was about 90% for a 34-year-old, 75% for a 37-year-old and 37% for a 42-year-old¹¹.

The model had limits. It hadn’t been checked against women who later used their frozen eggs, its assumptions may differ from clinic to clinic, and two authors worked for the genetic testing lab that supplied some of the data¹¹.

Age at freezing is the key number. ASRM advises telling women that live birth rates are better when eggs are frozen younger¹⁰.

What daily habits can and can’t change

Many fertility tips are folklore, while a few have solid support. Here is what a 2022 committee opinion from ASRM and the Society for Reproductive Endocrinology and Infertility found¹².

• Smoking. Women who smoke are more likely to be infertile, and they reach menopause 1 to 4 years earlier¹².
• Weight. Fertility is lower in women who are very thin or have obesity¹². The CDC lists weight extremes for both partners³.
• Alcohol. More than two drinks a day is probably best avoided while trying, and drinking should stop in pregnancy¹².
• Caffeine. One or two cups of coffee a day showed no clear harm. More than about 500 mg, over five cups, was linked to lower fertility¹².
• Positions and legs up. No evidence shows that position matters, and lying down afterward has no scientific basis. Sperm reach the fallopian tubes within 15 minutes¹².
• Saving it up. Holding off for more than five days may lower sperm counts. Sex every one or two days in the fertile window works best, and two or three times a week is nearly as good¹².
• Lubricants. In lab tests, common water-based lubricants cut sperm movement by 60% to 100% within an hour. Canola oil, mineral oil and products made with hydroxyethylcellulose didn’t. In real couples, though, lubricant use wasn’t linked to slower conception¹².

The fertile window is the six days ending on ovulation day¹². Our later article on fertility awareness covers tracking it.

These habits fit natural-health values well: food, movement, fresh air, and avoiding smoke and heavy drinking. Just don’t let waiting for a natural fix use up time you may need.

Supplements: what the biggest trials found

One supplement has clear backing, though it protects the baby rather than helping you conceive. ASRM advises women trying to conceive to take folic acid daily to help prevent birth defects of the brain and spine¹². Our prenatal vitamin article covers how to check labels.

For men, the largest test so far was run by NIH’s own scientists. The Folic Acid and Zinc Supplementation Trial gave 2,370 men either 5 mg of folic acid plus 30 mg of zinc a day or a placebo for six months⁵⁶.

Live births were 34% with the supplement and 35% with placebo⁶. Sperm counts, movement and shape didn’t improve⁵⁶. Men on the pills had slightly more sperm DNA damage, 29.7% versus 27.2%, and more stomach upset⁶.

A publicly funded 2025 review in the journal Nutrients covered 50 trials with more than 4,800 men, and it found no effect on pregnancy or live birth¹³.

Some products nudged a single sperm measure. CoQ10, for example, improved sperm movement by about 4 to 5 percentage points¹³. The certainty was low or very low, and most trials had design problems¹³.

The authors’ verdict: no convincing evidence that any dietary supplement helps male infertility¹³. ASRM reached a similar view for natural conception. It found little evidence that vitamin-enriched diets, antioxidants or herbal remedies improve fertility¹².

If a fertility blend cites a study, check who paid for it and whether it measured babies or only sperm numbers.

The fertility belief check

Belief	What the evidence shows	Rating
“Infertility is rare.”	About 1 in 6 people worldwide face it2	Evidence says no, or unsafe
“It’s usually the woman.”	Men are involved in about half of couples5	Evidence says no, or unsafe
“Stress is why you’re not pregnant.”	Distress before treatment didn’t lower pregnancy across 14 studies; stress that stops periods is different13	Evidence says no, or unsafe
“Men’s age doesn’t matter.”	Semen changes after 35; couples with older male partners report more trouble312	Evidence says no, or unsafe
“IVF can make up for age.”	Live births per retrieval fall from 50.7% under 35 to 7.9% over 4014	Evidence says no, or unsafe
“Frozen eggs guarantee a baby.”	About 5% to 7% chance per thawed egg; ASRM warns of false security10	Evidence says no, or unsafe
“Falling sperm counts mean most men are now infertile.”	Average counts fell in a big review, but critics dispute the meaning and fertility wasn’t measured79	Not enough evidence
“Fertility pills for men raise the odds of a baby.”	No gain in live births in a 2,370-couple NIH trial or a 50-trial review613	Evidence says no, or unsafe
“Folic acid while trying protects the baby.”	ASRM advises it daily to help prevent brain and spine birth defects12	Strong evidence
“Lying with your legs up after sex helps.”	Sperm reach the tubes in 15 minutes; no basis for lying down12	Not enough evidence
“Any coffee hurts your chances.”	One or two cups showed no clear harm; heavy intake did12	Evidence says no, or unsafe
“Smoking only matters once you’re pregnant.”	Women who smoke are more likely to be infertile and reach menopause earlier12	Evidence says no, or unsafe

When to seek an evaluation

The CDC’s timelines are a good starting point³:

• Under 35 with no known health or fertility problems: try for at least a year before seeing a clinician.
• 35 or older: see a clinician after six months of trying.
• Over 40: seek evaluation and treatment sooner still.

Those timelines are for couples with no known health or fertility problems³. If either partner has one, ask a clinician whether to come in sooner. Our later article on reproductive symptoms covers which signs can’t wait.

Bring both partners, and bring your questions. WHO calls infertility a medical condition, and a good clinician will treat it as one².

Questions readers ask

The bottom line

Infertility is common, it involves men about as often as women, and it is a medical condition rather than a personal failing. Everyday stress hasn’t been shown to lower the odds of treatment working, though stress that stops periods deserves care. Age matters most, and neither IVF nor egg freezing fully undoes it.

Not smoking, a healthy weight, moderate drinking and regular sex during the fertile window have real support. Men’s fertility pills have not shown more babies in the best trials. If you’ve tried for a year, or six months at 35 or older, it’s time to get both partners checked, and to be gentle with yourselves along the way.

Related reading

• Testosterone’s heart scare has eased, but its fertility catch has not
• Eleven of 12 Best-Selling Prenatals Missed a Label Amount. Check Yours
• What immune labels and tests mean, given that no single test measures your immunity
• Who paid for the study matters, even when the science is real
• Taking charge of your health helps, until it turns into blame

Sources

1. Boivin J, Griffiths E, Venetis CA. “Emotional Distress in Infertile Women and Failure of Assisted Reproductive Technologies: Meta-Analysis of Prospective Psychosocial Studies.” BMJ, 2011;342:d223 (Cardiff University ORCA record). pubmed.ncbi.nlm.nih.gov
2. World Health Organization. “1 in 6 People Globally Affected by Infertility.” News release, April 4, 2023; and United Nations Audiovisual Library (UNifeed), “WHO / Infertility Report,” Geneva briefing with Pascale Allotey, 2023. who.int and media.un.org
3. Centers for Disease Control and Prevention. “Infertility: Frequently Asked Questions.” Published May 15, 2024, accessed October 2026. cdc.gov
4. Nugent CN, Chandra A. “Infertility and Impaired Fecundity in Women and Men in the United States, 2015–2019.” National Health Statistics Reports No. 202, National Center for Health Statistics, April 24, 2024. cdc.gov
5. Eunice Kennedy Shriver National Institute of Child Health and Human Development. “Folic Acid and Zinc Supplementation Trial (FAZST).” NIH, accessed October 2026. nichd.nih.gov
6. National Institutes of Health. “Zinc, Folic Acid Supplement Does Not Improve Male Fertility, NIH Study Suggests.” News release, January 7, 2020. nih.gov
7. Levine H, Jørgensen N, Martino-Andrade A, et al. “Temporal Trends in Sperm Count: A Systematic Review and Meta-Regression Analysis of Samples Collected Globally in the 20th and 21st Centuries.” Human Reproduction Update, 2023;29(2):157–176. pubmed.ncbi.nlm.nih.gov
8. Hebrew University of Jerusalem. “Looming Crisis: Follow-Up Study Shows Significant Decline in Sperm Counts Globally, Including Latin America, Asia and Africa.” EurekAlert news release, November 15, 2022. eurekalert.org
9. Boulicault M, et al. “The Future of Sperm: A Biovariability Framework for Understanding Global Sperm Count Trends.” Human Fertility, 2021 (ResearchGate record). pubmed.ncbi.nlm.nih.gov
10. American Society for Reproductive Medicine Practice Committee. “Evidence-Based Outcomes After Oocyte Cryopreservation for Donor Oocyte In Vitro Fertilization and Planned Oocyte Cryopreservation: A Guideline.” ASRM, 2021. asrm.org
11. Goldman RH, Racowsky C, Farland LV, et al. “Predicting the Likelihood of Live Birth for Elective Oocyte Cryopreservation: A Counseling Tool for Physicians and Patients.” Human Reproduction, 2017;32(4):853–859. pubmed.ncbi.nlm.nih.gov
12. Practice Committee of the American Society for Reproductive Medicine and Practice Committee of the Society for Reproductive Endocrinology and Infertility. “Optimizing Natural Fertility: A Committee Opinion.” Fertility and Sterility, 2022;117(1):53–63. integration.asrm.org
13. Michaelsen MP, Poulsen M, Bjerregaard AA, et al. “The Effect of Dietary Supplements on Male Infertility in Terms of Pregnancy, Live Birth, and Sperm Parameters: A Systematic Review and Meta-Analysis.” Nutrients, 2025;17(10):1710. pmc.ncbi.nlm.nih.gov
14. Centers for Disease Control and Prevention. “2021 Assisted Reproductive Technology Fertility Clinic and National Summary Report.” CDC Stacks. stacks.cdc.gov