No sex position has been shown to improve conception rates. The American Society for Reproductive Medicine (ASRM) states there is zero evidence that position matters. Sperm reach the cervix within seconds regardless of how you do it. Use whatever position feels good.
If you've spent any time Googling "how to get pregnant," you've probably seen advice about sex positions. Missionary is supposedly best because gravity helps. Doggy style allows for deeper penetration. Woman-on-top is supposedly bad because sperm have to swim "uphill."
It all sounds logical. There's just one problem: none of it is supported by research.
What Actually Happens During Ejaculation
To understand why position doesn't matter, you need to know what happens the moment he finishes inside you.
Ejaculation deposits semen near the cervix. Within secondsânot minutes, secondsâsperm begin entering the cervical mucus. This mucus, which becomes thin and slippery around ovulation, acts like a highway that guides sperm toward the uterus and fallopian tubes.
The fastest sperm can reach the fallopian tubes in as little as one minute. Most arrive within 15-30 minutes. This happens regardless of whether you're lying flat, sitting up, or doing a handstand.
The key insight: by the time you could even change position or "help" the sperm along, the ones that are going to make it are already on their way. The stragglers left behind in the vagina? They weren't going to make it anyway.
Breaking Down the Common Claims
The claim: Gravity helps sperm reach the cervix when the woman is on her back.
The reality: Sperm don't need gravity's help. They're propelled by the force of ejaculation and then swim using their tails. The cervix isn't directly "below" the vaginal canal anywayâit's at an angle. Missionary is fine, but it's not better.
The claim: Allows for deeper penetration, depositing sperm closer to the cervix.
The reality: Depth of penetration doesn't affect conception rates. Semen pools near the cervix regardless of exactly how deep ejaculation occurs. The difference between "close to the cervix" and "very close to the cervix" is meaninglessâsperm enter the cervical mucus either way.
The claim: Works against gravity, making it harder for sperm to reach the egg.
The reality: Sperm don't care about gravity. They swim. The cervical mucus that transports them doesn't flow downwardâit guides sperm inward regardless of orientation. Woman-on-top is just as effective as any other position.
The claim: Gravity pulls semen out immediately, reducing chances.
The reality: Some semen will leak out in any position (this is called "flowback" and is completely normal). The sperm that enter the cervical mucus do so almost immediately. Standing doesn't prevent conception.
What About Deep Penetration?
This one comes up a lot, especially from guys who are... let's say, proud of their equipment. The theory is that a longer penis can deposit sperm closer to the cervix, giving them a head start.
Here's the thing: there's no evidence this matters.
The vagina is typically 3-7 inches deep when aroused. Average erect penis length is about 5-5.5 inches. Most men can reach the cervix or get close enough that it doesn't matter. And even if ejaculation occurs further from the cervix, sperm still enter the cervical mucus and make the journey.
Penis size has not been shown to affect fertility. Sperm from a man who's 4 inches reach the egg just as well as sperm from a man who's 8 inches. The swimmers do the work, not the delivery system.
What does matter is that ejaculation happens inside the vagina. That's it. The exact location and depth are irrelevant.
Does Lying Down Afterward Help?
You've probably heard you should lie flat for 15-30 minutes after sex, maybe with your hips elevated or legs up against the wall. Does this help?
The evidence is mixed at best.
Studies on IUI (intrauterine insemination) show conflicting resultsâsome found a benefit to lying down, others found no difference or even better results when women got up immediately. For natural conception, there are no controlled studies.
What we know for certain: sperm that are going to reach the egg enter the cervical mucus within seconds of ejaculation. Lying down for 15 minutes isn't going to change whether those sperm make it.
That said, lying down is harmless and might help you relax. If it makes you feel like you're "doing something," go for it. Just don't stress if you need to get up.
"There's no scientific evidence that any sexual position, or lying down afterward, improves your chances of getting pregnant."
â American College of Obstetricians and Gynecologists
What Actually Matters for Conception
If position doesn't matter, what does? Here's where to focus your energy:
1. Timing Is Everything
Sex during the fertile windowâthe 5 days before ovulation plus ovulation dayâis what determines your chances. The day of ovulation and the two days before have the highest probability. Position is irrelevant if you miss this window.
2. Frequency Helps
Having sex every 1-2 days during the fertile window gives you the best odds. Daily sex is fine and doesn't deplete sperm quality. More attempts = more chances.
3. Fresh Sperm Are Better Sperm
"Saving up" sperm actually makes them worseâolder sperm have more DNA damage. Regular ejaculation (including the day before the fertile window) keeps sperm fresh and healthy.
4. Enjoy Yourselves
Stress negatively impacts fertility. If you're anxiously contorting into positions you read about online, that's not helping. Relaxed, enjoyable sex is better than stressed, mechanical sexâand couples who enjoy the process have more of it.
Have sex in whatever position feels good for both of you. Do it frequently during the fertile window. Don't overthink the mechanicsâthe sperm know what to do. Your job is to get them there at the right time.
Find Your Fertile Window
Timing matters way more than position. Use our free calculator to find your most fertile days.
Calculate Ovulation âA Note on Fun
Here's something fertility advice often forgets: sex is supposed to be enjoyable. When couples start trying to conceive, sex can become scheduled, mechanical, and stressful. That's not good for your relationship or your fertility.
The best position is the one where you're both having a good time. Missionary every single time because you read it was "best"? That gets old fast. Mix it up. Enjoy each other. The goal is to have sex frequently during the fertile windowâand you're more likely to do that if it's actually fun.
So forget the optimization. Forget the gravity theories. Have good sex, have it often when you're fertile, and let the sperm do their job.