Health Advisor is a regular column where contributors share their knowledge in fields ranging from fitness to psychology, pediatrics to aging. Follow us @Globe_Health.

The art of being a woman is shared between friends, sisters, mothers and daughters, and aunts and nieces. We might learn to shave our legs from our mother, tie a sari from our grandmother, walk in high heels from our sister or make an old family recipe from our aunt. The art is interpreted and improved by the women in our lives with the goal of raising us to a higher aesthetic, domestic or cultural level.

What about the science of being a woman? Here we are falling short. Oh sure, we are fairly open to talking about menstrual periods, hot flushes, contraception and incontinence, but what about fertility? Fertility is the last unspoken scientific frontier of womanhood. We don't talk about how easy or hard it is to get pregnant. We don't talk about how long it might take or what the up and downsides are of waiting to try and conceive.

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Let's start the dialogue. Yes, I am talking to you, millenials in your 20s and 30s. I am talking to you as a Gen-Xer and infertility specialist who spends her day listening to women say, "if only I started trying to get pregnant sooner," or, "I guess I waited to long … I wish someone would have told me."

I am talking to you as a Gen-Xer who waited too long herself to conceive. I am talking to you with facts and figures your sister, mother and your aunt probably don't have, and if they do, they are likely not comfortable sharing them.

Here goes: You were born with a couple of million eggs, and you are losing eggs by the minute. Eventually, at menopause, you will have lost all of your eggs. Each year, from puberty to menopause, it gets harder and harder to conceive. On average, between age 20 and 30, your monthly chance of conceiving is 25 per cent and it declines from there. Beyond age 40, your monthly chance of conceiving is 5 per cent, and pregnancy after age 45 is rare.

Oh sure, you'll hear stories of your great-aunt's sister-in-law having a baby at 49, but those are as common as stories of painless periods or perfect skin. You should file them under "do not assume this will happen to me."

What you do with this information matters. If you are hoping to have a child using your own eggs (a child who will be genetically related to you), start considering how and when a pregnancy will fit into your life now.

If you are in a relationship, do not delay trying to conceive. Many of us want to wait until we have a house, ideal job or all of our debts paid off before having a child. Unfortunately, the wait to achieve most of those goals is years and usually covers peak reproductive years.

For example, the average age of a woman entering law school is between 25 and 30. She will finish in her late-20s or early 30s and then article. In her mid- to late-30s, when she finishes articling and takes a job, she might then feel ready to try and conceive. At that age, there is a 1 in 4 chance she'll be infertile.

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If you aren't ready to contemplate pregnancy now, you might consider egg-freezing. Egg-freezing involves removing eggs (usually 10 to 20) from your ovaries and freezing them. Then some time in the future, the eggs can be thawed and fertilized with sperm to hopefully achieve a pregnancy. "Hopefully" is the operative word, as the pregnancy rate from frozen eggs is not 100 per cent, so there is no guarantee of a child in the future. Egg-freezing is a gamble – a gamble with pretty good odds, but a gamble nevertheless. If you are considering egg-freezing, your best odds of success are before age 35.

While there have been tremendous scientific advances in fertility treatments, like in vitro fertilization (IVF), absolutely nothing can help you conceive with your eggs when they are too old. Our eggs have an expiry date, and for most women it's in their early 40s.

This science needs to be shared so women can make informed decisions about their fertility.

Understanding your fertility is as important to know as how to shave your legs or make your family's stew. After all, you might just want to pass along the art of being a woman to your daughter, an opportunity that time will take away if you waste it.

Dr. Beth Taylor is co-founder and co-director of Olive Fertility Centre (www.olivefertility.com and www.facebook.com/olivefertility) in Vancouver. She is a Clinical Associate Professor at UBC and coordinates the UBC Obstetric & Gynecology residency program "Reproductive Endocrinology & Infertility" rotation. She is an active staff member at BC Women's Hospital and Vancouver General Hospital and performs surgery at both of these centres.