In 2011, my oldest son, then just weeks shy of his eighth birthday, perched on the corner of my wife’s and my bed, his head tilted just far enough to the side so he couldn’t quite see the home birth of his baby brother. He wanted to be in the room; we told him he was welcome, and we prepared him for the moment.

In anticipation, we had purchased several children’s books about birth, some with vivid illustrations. We discussed with him in depth how the fetus grows into the baby that will be born from his mother’s uterus. I only fully realized later that we never explained how the baby got into his mother’s womb in the first place.

Although I consider myself a progressive individual, when it comes to discussing sex, apparently I have more Puritan in me than I had ever imagined. Over the years, when my son would ask about sex, I would hear a warning whisper in the back of my head: “Only answer the question being asked.” This cautionary voice would pop up only when sex was the subject.

If my son wondered about art, or history, or stars in the sky, I would never preemptively edit my answers — on the contrary. I’d want him to feel what it was like for those countless stars to just sit there in the immense beauty of the infinite universe. I’d want him to imagine exploring those stars figuratively and literally. I’d want him to dream of stars and look up every night, finding the one that guided him. I’d want him to walk away from our musings wanting more, not because I hadn’t been forthcoming, but because together we were just so fascinated.

Yet whenever a topic touched upon sex, my body would tense up, my words were limited, and I never over-answered the specific question asked.

When my son was 9, we took an ambitious and sprawling summer vacation. During the trip, he had the chance to connect with an amazing group of kids, and I perceived a difference in how he reacted to certain girls he met. Back home, I asked him about it. He knew just what I was talking about, and told me that he’d had a strange feeling in his body: this sensation started in the stomach area, touched his heart a little, but then shot down to his waist … and he didn’t have any idea what it was. I assured him that the feeling was normal. Relieved, he hoped aloud that this physical phenomenon would not happen again. I explained that it would happen again and that’s normal. “Okay,” he sighed, “but will it at least go away by the time I’m your age?” Nope. “Well, by the time I’m Grandpa’s age?” I told him that the feeling will likely be around his entire life. And here, my inner Puritan stopped me. “Answer only what’s asked,” the repressive mantra echoed in my mind. So rather than taking the opportunity to continue discussing what this feeling was about, the conversation ended.

At age 10, the subject arose again, when he wanted more information about how babies are created. I told him about the eggs women carry inside them (that felt safe) and about men’s sperm, and that a sperm and an egg need to come together to make a baby. (Science! Cut and dry.) But naturally, he followed up: How do the sperm and egg come together? I wasn’t sure how to respond. I was avoiding the question. In doing so, I wasn’t being the dad I aim to be. But I felt stuck. I was scared that I would trip over my words or I’d freak him out, or, well, scar him for life. I called a timeout. I told him that I needed to wait to answer his question. I’m sure he thought I needed to look up the answer.

Several weeks later, my wife and I attended a talk by Deborah Roffman, a sex education expert and author. Her latest book at the time was titled “Talk to Me First.” She started by explaining to us where Puritanical instincts originate: the actual Puritans. Sure, it’s an obvious revelation, but one that’s easy to forget. Our relatively young American society was largely built on a foundation of sex as sinful and virginity as virtuous.

It takes more than time to untangle that web; as parents, we can do our part. We influence the next generation’s stigmas, biases and inhibitions, and also its freedoms and forward thinking. Thus, as with other subjects, we need to be proactive proponents of truthful and thoughtful sex education.

Roffman acknowledged that there are age-appropriate ways of communicating what we think of as sophisticated information. To a 3- or 4-year-old, for example, you might simply offer that there are two pieces to a reproductive system; like two Legos, they fit together. Regardless of age, she stressed the importance of open dialogue, so, while the discussion might begin with babies and birth, it should be able to conceptually reach as far into the future as your child desires.

While listening to Roffman’s insights, I had my own epiphany on the subject. I was ready. I sat down with my son, brought up our recent, unfinished conversation, and went all in. I clarified that there are two halves to the reproductive system, and both are needed to create life. I described where the sperm resides and where the egg is, and exactly how the sperm and the egg meet. “The male penis is put into the female’s vagina.” My son looked at me with utter shock. “Dad, please tell me that you and Mom ONLY did that to get me and my brother.” Well, actually. … We covered it all. He asked a lot of questions, and I did my best to keep up. “How does the sperm come out of the penis?” I circled back to his experience a year prior, the feelings he had in his stomach and his shyness around some of the girls he met that summer. “That’s your body telling you things and sometimes when you’re an adult, you then share those feelings with the person you love.” He jumped in with, “Wait, I get it, it’s like a propeller on one of my toys: The energy inside you pushes the sperm out, right?” Exactly.

He was interested, but also grossed out. “I can’t ever imagine wanting to do that.” He asked if there’s any other way to have kids. He said he wanted kids but not like that. I mentioned adoption, which he already understood, and I covered in vitro fertilization. He then posited that if he understood the deeper reason humans need or want children, he would be less afraid of a process that, at that age, didn’t sound remotely appealing.

He thought in silence for a moment and then realized the question he really wanted answered. “Dad, why do people want babies?” I suggested that he ponder it himself and see what comes up and then we’d discuss it.

Later that day, he found me and declared that he had the answer. He looked at me straight in the eyes and with complete awareness stated, “It’s not about us as individuals; it’s about us as a world. We need children because we need people, to make the world a better place.”

I was blown away by his insight and at the same time not surprised at all. I acknowledged the thoughtfulness of his comment. He then paused and asked me his next question. “Why are we here?” And with that, “The Talk” I had been so hesitant to have with my son turned into the conversation about the stars in the sky and, ultimately, the meaning of life.

My son is now 13. He continues to ask questions of me and his mother about sexuality and everything else. We can’t imagine a more thoughtful, mature young man traversing the maze that is adolescence, and my wife and I are doing the best we can to keep up.

We are not perfect, but we realize the best way to make him feel safe to ask the questions is to answer them as fully and completely as we would with any other subject. We engage in the conversation, meeting him wherever he is, and allowing it to go wherever it needs to.

His younger brother is 5 and has never known a household of even slight Puritanical reticence. With him, the conversation really did start at birth, and when he starts thinking about sex, oh, we’ll be ready. (But he’ll probably just ask his brother.)

David Straus is a chief executive and social entrepreneur. He lives in California with his wife and two sons and is also a regular columnist for @davidstraus.

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