Home Soy foods Soy and your health Recipes with soy Soy candles Make own tempeh Soy news

Effects of soy on human reproduction

Some scientist have doubts about the adverse effect of soy consumption on human reproduction. High soy consumption may cause harm in the human population via its estrogenic or goitrogenic activities. However they say that more experimental and human research is required before any concusion can be drawn [1].

Animal studies show that soy phytoestrogens may damage the male reproductive organs. A review study indicates that these phytoestrogens may act as a endocrine disruptor [2]. Researchers at the Johns Hopkins School of Public Health found that pregnant rats a diet laced with genistein may harm the male fetus, possibly affecting future reproduction [3]. A study that made headlines examined the association of soy foods and isoflavones intake with semen quality parameters [4].
This study found an inverse association between soy food intake and sperm concentration. There was no effect on sperm motility, sperm morphology or ejaculate volume. This study was limited to only 99 men and the author wrote that more research is needed to prove that soy actually reduces male fertility.

Many studies have demonstrated a possible adverse effect of soy intake on human and animal reproduction. However, these findings have not been confirmed in epidemiological studies. For example, Asians who consume a lot of soy products don't have more problems with decreased fertility than populations with low soy intake.


[1] Goitrogenic and estrogenic activity of soy isoflavones. Environ Health Perspect. 2002 Jun.
[2]Soy, phyto-oestrogens and male reproductive function: a review. Int J Androl. 2010 Apr.
[3] Transplacental transfer of the phytoestrogen daidzein in DA/Han rats, Archives of Toxicology, Feb. 2002
[4] Soy food and isoflavone intake in relation to semen quality parameters among men from an infertility clinic. Hum Reprod. 2008 Nov.


Can soy creates hormones inbalance

My husband and I have been using soya for the pass 5 years. we have also been trying to have a baby during those years. I recently met someone who told me that drinking soymilk might be the cause. He said that soy creates hormones inbalance. could that be true.
Guest - 05/05/2005

Can soy creates hormones inbalance

Soy contains chemicals called pseudo-oestregen. While those defending their economic interests with very one-sided propaganda, will state that there are only positive effects to soy (or anything else), the truth is that one should always remain scepticle (if it sounds too good to be true, it usually is). Just because wine (alcohol) and asprin can benefit older people with high risk of strokes and heart attacks, does not mean that the negative side-effects and risks are less for everyone else. Over-use of just about anything is unhealthy.

Scientific research at university of Belfast has found that overconsumption of soy (that is a 'secret' ingrendient in just about everything we eat) has been found to reduce male fertility (because of the pseudo-oestrogens, female hormone).

In today's world, it's pretty hard to know what is being fed to us anymore. Concentrations of pesticides, mercury, dioxin, nitrate.. and to top all of that, genetically modified foods, where they focus on the benefits for you and all the hunger in the world it could cure. The truth is, the benefits are only for the large multinationals, who put smaller farmers out of business, and increase profit margins. The question shouldn't even be "is it healthy for you", but "is it beneficial to our environment, nature, birds and the bees". See, there are much better, safer, healthier and morally and ethically correct ways to improve quality of life.

I'm not a vegetarian, conservative, religious or anything.. just critical and conciouss like we all ought to be (and yes, I'm European), but we depend on INDEPENDENT sources of information, not those provided by industry sponsored research and propaganda. I prefer natural flow of things that have stood the test of time and ensured checks and balances. I see great threat in disturbing these balances in the most intrusive way imaginable, where the most important test of checks and balances is omitted by the rush for patenting and market domination: the test of time.

There are however a lot of other facts that can decrease fertility.. stress, temperature (tight undies, laptops, etc.), genetics, etc.
Some get pregnant the first time they ever have (unprotected) sex, unintended, and some try for more than 10 years. Sounds cliche, but sometimes trying too hard decreases the chances.. due to stress or over use icon_smile.gif

Perhaps wearing loose boxers in winter, and no more than 1 try a week, might increases chances, rest well, eat well... you can try tracking your temperature to know when you've 'popped an egg' icon_smile.gif

Good luck.. if all fails, try extra marital affairs.. just kidding.. don't adopt, .. if you have the best interest of the child in mind (not just food and clothes, but also their sense of identity, culture and other things important to an individual), consider becoming a foster parent.. try medical solutions, but don't go to extremes, have others carry your baby, or other extremes. People have accidents, die, lose libs, get paralized, and what not.. and still manage to find ways to appreciate life. Surely if all failed, you could find ways to accept not being able to have kids, and still be surrounded by kids every day until you get sick of them. I'll let you babysit my kids, and on a bad day, I might even let you keep them.. hehe, just kidding.. (I don't even have kids. Peace.
Fonz - 14/09/2005

Can soy creates hormones inbalance

Soy does creat hormone imbalances for both men and women and has a host of other unhealthy side effects, it's only a matter of time before they show up. Lots of research out there.
Julia - 15/11/2006

Is it OK to give BOYs soy milk?

Hi, I'm writing from Brazil and here we have a soy milk with fruit (grape/apple or pineapple). My question is: is it OK to give BOYs soy milk? Some people say that it has toomany "femine hormones"? Can you answer me? Thanks a million,
Shirley - 05/12/2006

Is it OK to give BOYs soy milk?

Indeed I have read that soy is rich in estrogen type substances. Parents who feed their children soy-based formula should be aware of its extremely high phytoestrogen content. Some scientists have estimated a child being fed soy formula is ingesting the hormonal equivalent of five birth control pills a day (116). Such a high intake could have disastrous results. Soy formula also contains no cholesterol, vital for brain and nervous system development.

Though research is still ongoing, some recent studies have indicated that soy's phytoestrogens could be causative factors in some forms of breast cancer (117), penile birth defects (118), and infantile leukemia (119). Regardless, soy's phytoestrogens, or isoflavones, have been definitely shown to depress thyroid function (120) and to cause infertility in every animal species studied so far (121). Clearly, modern soy products and isolated isoflavone supplements are not healthy foods for vegetarians, vegans, or anyone else, yet these are the very ones that are most consumed.If you like, this is the website I got the

Again I am seeking more info to feed the fire and compare as much data as I can obtain to make my opinion more balanced on both sides
Julian - 10/12/2006

Is it OK to give BOYs soy milk?

Shirley, you did not mention the age of your boy. Up to the age of 6 months, babies should only drink mother's milk, not cow's milk or soy milk. After the age of 6 months special formulated milk (on basis of soy or cow's milk) can be given to babies. After the age of 1 year it's safe to give soy milk to children. Soy does not contain oestrogens. Not 1 molecule! It contains isoflavones which have a similar structure but not same function. Actually, isoflovones can even reduce the bad effects of natural oestrogens.

Julian, thanks for your input but the website Westonprice is not a reliable source. That site is only promoting meat. It's a questionable organization at
Rob - 12/12/2006

soya myths and science

No, soya does not create hormonal imbalances. Check out for an overview of the science. Phytooestrogens - the hormones you mention - are a naturally occuring plant hormone. in soya, they are 1,000 times weaker than the hormones in cow's milk - which creates far more havoc in the human body than soya ever did.
Jane - 22/09/2010

Soy formula

I gave my daughter soy formula because the doctor advised it. Yes, it did rush her in adolesence. At 17 she became a sex addict. I believed it was her advanced hormones, but never read about soy until now. She has many health problems and is very delicate. My other 5 daughters did not take soy as babies.
Beverly - 22/09/2010


hi there!
I would like to ask about the soya milk.Is it true that drinking or eating soya milk can lessen the sperm of a man?
I'm hoping that you can give me an answer... - 07/05/2011

Soya milk

I assume that you refer to a recent study, published in Human Reproduction,investigating the association of soy foods and isoflavones intake with semen quality parameters, that caused a lot of media coverage.
According to this study, soy count does not affect total sperm count, ejaculate volume, sperm motility or sperm morphology. The researchers found that soy consumption lowered sperm concentration, but the total sperm count was the same because of higher ejaculate volume. This study also concluded that the clinical significance of these findings remains to be determined. This study is confounded by many issues and we believe that there is no clinical significance at all.
Rob - 08/05/2011

Sperm count and soy

whew. thank god it is not true. it would have been a really big con for soy.
ronaldhill - 08/08/2011

Sperm count and soy

I agree with Rob. Soy does not affect the total sperm count,only its concentration because of higher ejaculate volume. Soy causes no harm to health,it is very nutritious. I've been drinking Soya milk for years because studies show that Soy prevents cancer.
Julia77 - 08/10/2011

soy products and puberty

Hi, just a comment from the other side of the fence, my daughter has been drinking soy milk every day for 10 years and is now 13, she has not yet begun to menstruate so no precosious puberty here.
ctl - 08/11/2013


Can yoy say whether using soya products reduces a woman's ability to become pregnant?
Petal40 - 14/07/2018


Countries where soy products are consumed in large amounts, such as many Asian countries, have no lower birth rates than countries where soy is not routinely consumed. Kenneth Setchell, professor of Pediatrics at Children's Hospital and Medical Center in Cincinnati, confirms that soy does not prevent ovulation and a normal menstrual cycle, although soy may lengthen the menstrual cycle. However, it is possible that any type of food can have a special effect on individual women.
Rob - 14/07/2018

is soya good for girls aged 6-10 years old

how safe is edamami to eat for a growing girls age 6-10 years. does soya make harmonal changes abnormal or faster. worried mom. please reply.
bonnie singh - 19/05/2019

is soya good for girls aged 6-10 years old

There are no indications that eating soy (and edame) has a negative influence on the development of young girls. There are no studies linking adverse effects of soy isoflavones to normal growth and development. Girls start not menstruating earlier due to soy consumption. In Asian countries, including Japan, China, Vietnam, Indonesia and the Philippines, soy forms a large part of their diet. Breast cancer rates in these countries are much lower than in Western countries, where less soy is consumed. Migrant studies show that women, who come to the US from Asia, in their adult life, have a much lower risk of breast cancer. This could be explained by their consumption of soy during their adolescence. In contrast, those Asians who are born in the US have the same risk of breast cancer as other American women.

A study titled "A Lifetime of Eating Soy May Lower Breast Cancer Risk" and published in Carcinogenesis (Volume 23, No. 9, 2002, pp. 1491-1496) concluded that Asian-American women who ate a lot of soy, from adolescence to adulthood, were significantly less likely to develop breast cancer.
Rob - 19/05/2019

Hormone overload with soy milk?

My mother is concerned that my 3 year old will have early menses or a hormonal imbalance because she is drinking so much soy milk. I try to limit her to 28 oz. daily. She went from breast milk to soy at about 14 months. She does not have a milk allergy, but my older 2 had horrible ear problems and I wanted to minimize her problems. She has not had any problems with her ears,I am glad to say. Do you think that there is any basis for the fears my mother has about "hormone overload" with soy milk?
Ronda - 07/08/2020

Hormone overload with soy milk?

Cow's milk can indeed cause problems such as ear infections. Soymilk does not contain hormones but they contain phytochemicals (isoflavones) which are similar in structure as estrogen. Consuming normal quantities of soy milk does not cause any negative influence on the development of children. There's no indication that girls start menstruating early due to soy consumption. To the contrary, the consumption of soy products during puberty might reduce the risk for breast cancer later in life.
Rob - 07/08/2020

Add your comment


Email (optional)



Fill in anti-spam code 175