Sorcha Grisewood was 36 when she knew, without a doubt, that she didn't want to have children. The primary school teacher from Dublin never heard the ticking of the biological clock or felt the broodiness her friends experienced when they reached their thirties. Baby fever? She just never got it.
Like most people who are child-free by choice, Sorcha, who is now 41, has several reasons for opting out of parenthood - some of them personal and some of them ethical.
She values "freedom, travel, adventure, creativity, spontaneity", and the ability to do what she wants when she wants. But Sorcha is also acutely aware of the environmental impact that children have "on an already overpopulated planet".
"With everything that is going on in the world and the cost of raising a child… you're breeding another consumer who is only going to consume more of the world's already scarce resources," she tells me.
"Pope Francis said not having children is selfish but I actually think it's the opposite because people who don't have children have generally given it a lot of thought. They've made an ethical decision in a way - a conscious decision."
The environmental toll of having children has become a hot-button issue in recent years. A 2017 study published in Environmental Research Letters found that the greatest impact a person can have in fighting climate change is by having one less child.
Living car-free, avoiding long-haul flights and going vegetarian can also make a difference, said the researchers, but the impact is a drop in the ocean compared to the 58.6 tonnes of Co2 equivalent that one child generates for each year of a parent's life.
This particular study got people talking, and while there is still much debate on the carbon emission figures attributed to one child (some groups say it doesn't take into account the climate targets that will limit environmental damage in the future) and the impact of individual action when compared to system change, there is no question that the next generation is inheriting a climate emergency.
It's a concern that looms large over younger adults, especially after several well-known faces pledged to limit the number of children they have or opt out of parenthood altogether.
American singer Miley Cyrus has revealed that she worries about the planet her children might inherit. "Until I feel like my kid would live on an earth with fish in the water, I'm not bringing in another person to deal with that. We don't want to reproduce because we know that the earth can't handle it," the 27-year-old told Elle magazine.
"We just take and take and expect it to keep producing. And it's exhausted. It can't produce. We're getting handed a piece-of-s*it planet, and I refuse to hand that down to my child."
Prince Harry has also shared concerns. In an interview with primatologist Jane Goodall for a special edition of British Vogue, he revealed that he and wife Meghan Markle will have two children "maximum" because of climate change.
"Surely, being as intelligent as we all are, or as evolved as we all are supposed to be, we should leave something better behind for the next generation," he added.
Women-led networks are also bringing awareness to the environmental threats that future generations face. US-based organisation Conceivable Future is made up of people who "can't imagine bringing children into such a hot, troubled world", as well as parents who are deeply concerned about the environment their children will inherit.
Another group, BirthStrike, was founded in 2018 before disbanding in August of this year. The organisation was made up of people who didn't want to bring children into a planet on the verge of climate catastrophe. They demobilised after a series of media reports inaccurately suggested that they were trying to offset their individual carbon footprints rather than focus on systematic change. For Deirdre Lane, a sustainability advocate from Kildare, the decision not to have children is based on several factors, but paramount are her concerns about climate change and its consequences.
"Take earlier this year, when we ran out of water," she says. "This is Ireland where we're running out of water! This isn't California that's on fire. This is today in our country. I think we really have to reflect on our own legacy as a planet. We've only one planet."
As Earth Hour's Ireland ambassador and the founder of the Shamrock Spring movement, Deirdre has of course considered the carbon footprint of parenthood and gasped at the environmental impact of disposable nappies. Yet she doesn't place too much emphasis on the immediate or tangible impact of her decision. The real impact she is making, she argues, is as a campaigner. By not having children, she has more time and energy to raise awareness and campaign against climate change.
"[Being child-free] gives you that freedom of not having to be back to cook the dinner at 6pm," she says. "I can work through the night. I can travel through the night. I can be online to help my network - my babies. I've given birth to so many projects and empowered so many other people to deliver long-term sustainable solutions."
And if these sustainable solutions were already in place - would she have children then? There's a short pause before she replies.
"When I first went to the Cloughjordan Ecovillage, there was a very handsome man there and I asked him why he was living in an ecovillage and he said it's because we can have free-range children. How many towns in Ireland - or streets or homes - have the privilege and the luxury of having free-range safe space for children?
"I started my mothering early," she adds. "I'm the second child of six children. I was always mothering somebody and then I was godmother to my sister at age 11 so I'd all that mothering responsibility really early.
"So you had Peig in one hand and a sibling on your hip… and I'm a phenomenal auntie!"
The child-free contingent is growing in Ireland, as parenthood becomes less of an expectation and more of a personal choice. But there is still very little research on the experiences of child-free people and their individual reasons for opting out.
Niamh Madden from Tullamore led a small survey on the phenomenon late last year, shortly before she founded Sisterhood, a community for child-free women in Ireland.
Over 300 women responded, citing reasons such as freedom, career and life goals and the fact that they were already fulfilled. Only 3pc of respondents cited environmental reasons but Madden has noticed that the topic has become more of a talking point among Sisterhood members in recent months.
"I don't know if it's a sense of pride in having chosen this path and kind of thinking, 'actually, I am doing something good for the world'," she says. "They might have received comments like 'you're selfish' or 'you'll change your mind' but now there is a sense of 'well, I'm actually doing something good for the environment'.
"There's definitely more chat about it and a sense of not wanting to contribute to a planet that is already struggling to survive."
The link between ecosystem destruction and the Covid-19 pandemic may have also given people pause for thought, she suggests. A survey by the US-based Guttmacher Institute, a research group that advocates for reproductive rights, found that 34pc of women said the pandemic was causing them to delay getting pregnant, or to have fewer children. Respondents didn't outline their exact reasons but it's fairly safe to conclude that the threat of future pandemics was one of them.
People have certainly become more aware of the planet they are leaving for their children. Five years ago, the link between parenthood and climate change was rarely, if ever, broached. Nowadays, there are more resources for those who are questioning whether or not to have children - and the environmental impact of having children has emerged as one of the key considerations.
Sorcha Grisewood says the Maxine Trump documentary To Kid or Not To Kid helped to solidify her decision. "One of the considerations in it was the environmental impact that all of us humans are having on the planet… it's a very thought-provoking documentary," she says.
Dr Julie Rodgers of the Maynooth University Motherhood Project says she's particularly struck by the number of new novels that are "considering this question of motherhood and global crises, whether that be climate, poverty or recession".
"I think a great example of that is Emma Donoghue's The Pull of the Stars which looks at the experience of childbirth and new motherhood during a pandemic… the draft had been completed before Covid-19 broke out. Even Emma Donoghue herself would say that this is insane that her book has come out at this time.
"Another really recent one is Jenny Offill's Weather and a few years ago there was Megan Hunter's The End We Start From which looks at childbirth and new motherhood in the middle of massive floods… There's almost now what you could call a body of motherhood literature that is very much contextualised within health crises or climate crises. And the fact that that is a growing body of fiction is, in and of itself, incredibly telling."
Podcasts that examine the child-free experience have become more popular too.
Margaret O'Connor, a psychotherapist based in Limerick, recently launched Are Kids For Me?, a podcast that speaks to people who have chosen not to have children and which acts as a companion of sorts to her counselling service of the same name.
O'Connor set up the service in 2018 when she recognised that people may need help in both making the decision and, as she puts it, living with the decision.
She works with both individuals and couples who are trying to decide whether or not to have children and she says environmental concerns often come up as part of the conversation.
"It would be mentioned but it wouldn't be a sole factor, and generally there's a mix of factors for everybody anyway," she says. "But it would be mentioned around the area of sustainability and the impact on the world's population.
"It's not a one-off decision," she adds. "You don't make it and never think about it again… They will come back, check in, reflect - and I think even if you make the decision to be child-free, I think you still generally need some support because you're well in the minority and it might cause some issues as you go through your life."
Sorcha says she made the decision not to have children over the course of years. She weighed up the pros and cons and considered all the angles and yet, even today, she still fears judgement when she tells family or friends.
"You do feel like you have to justify yourself, especially as a woman," she says. "The nature of my job as a primary school teacher, you're surrounded by women and you're constantly talking about kids - a lot of teachers would have their own children as well as the kids that they teach.
"There is kind of an assumption I think in my job that you're going to have kids. People don't pry but the conversation would come up - 'have you got kids of your own?' - and it tends to shut down the conversation fairly quickly if you say that you don't."
Deirdre agrees that the subject can provoke strong reactions from people. "They get so angry because it brings up something in them," she says. "It's a bit like shadow boxing - a lot of people resent the freedom they don't have because they have to go home to children… It's like a bucket list for some people.
"So many mothers want grandchildren as part of their social equity," she adds. "'Who's going to mind you when you're older?' and it's like, well, is that why you brought children into the world?"
Of course, while the decision not to have children is a conversation that some child-free people avoid having with friends and family, it's an unavoidable conversation in a long-term romantic relationship.
Sorcha, who is currently single, says it wasn't an issue with her previous partner. "He was actually completely on board," she explains. "We had that in common. He didn't mind that I didn't want kids - it wasn't an issue and it wasn't the reason we broke up."
Deirdre doesn't think of it as a deal breaker - at least in the initial stages of a relationship. "I've been in several long-term relationships and a guy, when you meet him first, he's never going to say, 'I want you to be the mother of my children'. One guy did but at no point when you meet someone do they say 'let's make babies!'"
It's not something she has given much thought to, she adds, before asking: "How many men have you asked this question to?" [The honest answer is zero. Despite my better attempts, I couldn't find one man who was willing to speak publicly about it.]
Julie of the Motherhood Project isn't surprised to hear that child-free men were less willing to talk about their experiences. "Where I stand on that is that it is more definitive for women. You have to make a choice because, after a certain age, you will no longer be able to bear children… if you want to have a biological child, there is a cut-off point.
"And men I don't think have to come down firmly and possibly even have to engage with it in a decisive way because the option to biologically procreate remains for the man until a much later stage in life… women don't get to revise the option."
Put another way, women are still bearing the brunt of social judgment should they choose to remain child-free, as well as the burden of having to make the decision.
"I think as a society we don't celebrate women who choose not to have children - as if it's a decision they should be ashamed of," says Sorcha. "What really is unique or original about an experience that almost every woman on earth has at some point - having a baby? I mean, obviously that child is unique but the experience of it isn't. Does the world really need more people? Isn't it already over-populated?
"Aren't we already destroying our planet without adding to that problem by breeding more humans to continue the cycle of consumption and environmental destruction?"
Julie thinks we need to have more open and honest conversations about the "restrictive ideology" of motherhood and the "alternative pathways" that women can take.
"I decided to only have one child and that's for a number of reasons," she explains.
"I've made a decision not to have any more children because of the general conditions of our world, such as the ecological crises, the growing poverty, health crises, the ongoing unequal share of the burden between women and men when it comes to mother work, the impact that mother work has on your career, and furthermore, the very prescriptive ideas of how we should mother that exist out there. I wanted to have one and was lucky enough to be able to have one."
Julie is clear and decisive as she shares her reasons, but what about those who are still undecided, or those who can't reconcile their biological urge with their increasing climate anxiety? How do they decide whether or not to have kids when the decision is more complex than ever before?
Margaret, who has counselled hundreds of people through the decision, offers some advice.
"Really, we're all making the best decisions that we can," she says. "You may never be 100pc sure but I guess you're trying to be as open as possible to all the possibilities and trying to put yourself in the different scenarios of 'I will, I won't' while not getting caught in a battle of logic. It's really trying to see what resonates with you, what sits with you, what appeals to you.
"What comes up a lot is people feeling very pressured around time and feeling very pressured that there is a specific 100pc correct answer for them - and really, that doesn't exist."