Women are taught that having a child is the only proper way to seek fulfillment.

They grow up learning they must become pregnant, give birth and experience the wonderful joys of motherhood – and if they don't, they can't possibly have lived a complete life.

Lately, however, there's a growing trend toward childlessness. The US Census Bureau reported in 2014, 47.6 percent of women ages 15 to 44 were childless.

That's the highest percentage of childless women since the Bureau started measuring the percentages in 1976.

That same year, the percentage of childless women ages 25 to 29 hit its peak at 49.6 percent.

And the amount of childless 20- to 24-year-old women increased by almost 4 percent in two years – from 71.4 percent in 2012 to 75.2 percent in 2014.

The women who make up these percentages, whether by choice or not, often experience unfair criticism and judgment.

They're regarded as selfish, lazy and self-serving. They experience shame and alienation.

Their mothers whine about why they won't give them grandchildren, and Christmas dinner is really awkward.

But there is a variety of reasons a woman wouldn't want to have children – none of which make her any less of a woman.

1. Because some women physically can't.

According to the Centers for Disease Control and Prevention (CDC), about 6 percent of married women ages 15 to 44 are infertile – that is, they are unable to get pregnant after having one year of unprotected sex.

Infertility can be caused by age, rapid weight loss or gain, excessive alcohol use, smoking or excessive stress that causes missed periods.

2. Because two is just enough.

The idea that marriage is just for reproducing is becoming more and more obsolete.

Although the vast majority of married women do end up having children, some women don't really want a full house, and that's OK.

In 2013, Sara Tenenbein, a 31-year-old blogger and consultant, told The Los Angeles Times she's satisfied living with just her husband and doesn't "need to add more humans to the equation."

And she's not alone: Between the years 2006 and 2010, 6 percent of married women ages 40 to 44 had no children (biological, adopted or stepchildren) in their house.

It's a small percentage, but it's statistically significant since in 1988, only 4.5 percent of married women were childless.

Childless by Choice Project Director Laura S. Scott also told The Los Angeles Times that recently, there's been a "resistance" to becoming a parent right after marriage.

People are taking control of their own lives and refusing to follow previously accepted trajectories “in ways that they didn't perhaps 30 or 40 or 50 years ago," Scott said.

3. Because there are not enough social services to assist working mothers.

Paid maternity leave, flexible work schedule and subsidized day care are all necessary requirements for a woman who'd at least try to have it all.

The United States has a notoriously flawed maternity leave system – mainly because paid maternity leave simply doesn't exist.

President Obama has called the US the only developed country in the world that doesn't have some kind of partially paid, legally protected time off program for new mothers.

Swedish mother Christine Demsteader told Bloomberg she has it "so good" in Stockholm.

“The thing is," she said, "we have only one system for doing things: Women take a year off, then they go back to work, and the kid goes into day care. You don’t have another option.”

Maybe if the US helps women who want to have kids, women will have kids.

4. Because of intelligence... maybe.

Research from the London School of Economics suggests there's a link between intelligence and desire to have children.

According to Evolutionary Psychologist Satoshi Kanazawa, a woman's urge to be a mother drops 25 percent for every 15 extra IQ points.

But Sadhbh Walshe of The Guardian wasn't convinced, and she analyzed these results even further.

Walshe proclaims Kanazawa's findings merely reinforce the terrible idea that women who choose not to have children are selfish. She says:

[Kanazawa's] ultimate conclusion, however, is that intelligent women's failure to reproduce is bad for them because they are flying in the face of their biological destiny, and it's also bad for society because fewer intelligent moms means fewer intelligent kids, and that may have drastic implications for the nationwide IQ.

So put another way, smart women are doing society a disservice with their dumb reproductive choices.

This plays nicely into the narrative that women who choose not to have children are selfish or sad or both.

Kanazawa's findings might seem interesting, but they should be taken with a grain of salt. He has an history of being under fire for a variety of controversial pseudoscience – his most heinous being his "objective" suggestion that black women are not attractive.

It's worth noting women who have achieved high levels of education are generally the least likely to have children, but in recent years, their percentage of childlessness is actually decreasing.

Women with professional degrees are more likely to have children now than they were 14 years ago. In other words, they're actually going against the trend.

5. Because of negative interactions with children.

A study from Kansas State University suggests people who have been exposed to loud tantrums, smelly diapers or other gross, unappealing aspects of babies don't want to have children.

Yeah, this makes sense.

6. Because of increased use of emergency contraceptives and birth control.

The CDC reports 11 percent of sexually active women between the years 2006 and 2010 used the morning after pill at some point in their lives, compared to only 4.2 percent in 2002 and 1 percent in 1995.

Additionally, the percentage of women who have used contraceptive methods has increased from 98.2 percent in 2002 to 99.1 percent between 2006 and 2010.

Of those contraceptive methods, 87.5 percent of women used highly effective methods such as the pill, an IUD or a contraceptive patch, up from 85.5 percent in 2002.

Emergency contraceptives and birth control methods give women agency over their own bodies, allowing them to decide when they feel ready to have a child – if ever.

7. Because they just don't want to.

Ultimately, having a child is an individual choice. And some women just don't want to do it.

Women are experiencing a kind of freedom they've never had before.

Gone are the days when women could only be housewives, when they felt pressure to stay in the home and be their families' caregivers.

Now, women are in every corner of every industry, with their representation growing each day.

It's this plethora of new choices that make women feel like they can truly do anything.