For years, women trying to conceive have been encouraged to "lie back and think of England".
But now scientists have said sexual positions make no difference to conception chances - as a major study debunks myths that women trying for a family should lie on their back after sex.
The research tracked almost 500 women who were trying to get pregnant.
Half were asked to remain in bed for 15 minutes after intercourse, with knees raised, following age-old advice.
But the study found it made little difference to pregnancy rates - and in fact, women who got up immediately afterwards fared slightly better.
Fertility experts at the European Society of Human Reproduction and Embryology annual meeting said there was no reason to stay in bed for longer than it takes "to get your breath back".
Encouraging couples to be as adventurous as they wanted to be in the bedroom, they also suggested too many of those trying to conceive forgot how to enjoy sex.
Stuart Lavery, consultant gynaecologist at Hammersmith Hospital, said: "People come into the clinic and ask about sexual positions and the best way to conceive.
"They tell me that they have sat with their legs up against a wall, or that their husband puts a pillow underneath their bottom. Loads and loads of people do it."
In fact, the honest answer was there was no evidence that any position was more successful than any other, he said.
Prof Allan Pacey, Professor of Andrology, University of Sheffield, said couples heard all sorts of myths about the best way to achieve conception.
"I've heard all sorts of things like women holding their legs in the air and doing the cycling motion with their legs in the air," he said.
"I don't think there is any evidence to suggest one thing is better," he stressed.
Researchers said it took just five minutes for sperm cells to reach the fallopian tube, after which they can survive for several days in the womb.
"In the time it takes for someone to have a cuddle and get their breath back, the sperm that are going to do their job, are already in there, they're pretty quick," he said. "In any position."
Dr Adam Balen, chairman of the British Fertility Society, added: "The important thing to say, is that if you want to get pregnant, have lots sex - as much as you want, however you want - and enjoy it, rather than focus on the time of ovulation."
He said there was a lot of confusion about female anatomy, which meant many couples imagined a straight vertical line between the womb and vagina.
"The vagina is tilted and the womb is then tilted relative to the vagina and fallopian tubes and the ovaries, so it is not just one passage," he said.
Experts singled out just one bedroom act which would damage conception chances - lighting up a post-coital cigarette.
"After you have had sex, do whatever you want but don't smoke," Dr Balen said.
Fertility doctors said that too often, couples clutched at straws about how to improve conception odds.
One study which found women who had more orgasms had higher pregnancy rates but researchers later found that women who enjoyed more orgasms were simply likely to have more sex.
The new study by the VU University Medical Center Amsterdam involved 479 women undergoing artificial insemination. Women who had 15 minutes bedrest afterwards achieved pregnancy rates of 32.2 per cent, while those who did not achieved slightly higher rates of 40.3 per cent.
Lead researcher Joukje van Rijswijk said: "We believe our results in such a large randomised trial are solid, and sufficiently strong to render the recommendation for bed rest obsolete," she said.
Advice | Types of fertility treatment
No single fertility treatment is best for everyone. According to the NHS, the right treatment will depend on patients' circumstances, including the age of the female partner and medical history.
Broadly speaking, fertility treatments fall into three categories:
These are usually prescribed to women. Most of the common fertility medicines, such as clomifene, are intended to help with ovulation problems.
These include fallopian tube surgery, which can be helpful if the fallopian tubes, which lead from the ovaries to the uterus (womb), become blocked or scarred, preventing pregnancy.
This can include intrauterine insemination (IUI), in which sperm is placed into the womb using a fine plastic tube. This can be helpful in cases of mild sperm problems.
Assisted conception also includes IVF (in vitro fertilisation), in which sperm and eggs are mixed outside the body and put back into the womb. This can be helpful for a range of fertility problems, including more severe sperm problems and cases of unexplained infertility.
The confusing advice on how women can conceive
1995: Drink wine
According to the Danish Epidemiology Science Centre in 1995, women who regularly drink red or white wine stand a better chance of conceiving within two months than women who prefer beer and spirits - or don't drink at all.
2009: Stop drinking
Dr Jan Gill, from Queen Margaret University's Alcohol Research Group, said in 2009 that alcohol can affect a woman's fertility while a Drinkaware spokesman said there is evidence to suggest heavy drinking can affect men's fertility too.
2010: Be honest about your weight
According to a 2010 University of Texas Medical Branch at Galveston study, nearly 48 percent of underweight, 23 per cent of overweight, and 16 per cent of normal weight women of a reproductive age don't accurately assess their own body weights. This could have an impact on their health habits, which could then affect their fertility.
2011: Ditch caffeine
A 2011 University of Nevada study found caffeine can affect fertility by reducing muscle activity in the fallopian tubes that carry eggs from a woman's ovaries to her womb.
2011: Don't be too thin
Women with a BMI of 14 to 18 - who are typically classed as underweight - could be less likely to conceive naturally, according to the Advanced Fertility Center of Chicago in 2011.
2014: Lose 5kg
According to a 2014 study from the American Society for Reproductive Medicine, if women drop a dress size, they can get pregnant faster. Women who lost 5kg took on average two and a half months to fall pregnant, rather than three months for those who didn't lose weight.
2016: Lose 4kg
A 2016 University Medical Centre Groningen study found that if women lose 4kg on average in six months through exercise and a better diet, their chances of getting pregnant naturally more than doubles.