So much has been said about nature versus nurture that I would be inclined to say it's not even a very interesting discussion anymore, except that it still comes up in conversation really all the time. My two kids have the same parents and live in the same house, yet they clearly have their own, individual personalities. Anyone with siblings could point out differences and wonder how children growing up in the same circumstances develop distinct preferences and characteristics. I wonder several times a day if my daughter's tantrums are a result of my failure as a parent or a result of the cognitive deficits inherent in being a 3-year-old. Then I remember that, even if I'm not at my best as a parent, the tantrums are definitely the fault of the 3-year-old brain.
It sounds horrible, but I suspect that other parents will agree with me when I say that I find comfort in seeing other people's kids melt down in public. It's such a relief to know that it's not just me. It's a further relief when I see those kids continue to throw themselves on the ground even if their parents handle the tantrums more calmly than I do. Anyway, I realize I'm not exactly answering your question, but my point is, the stroller you choose is a tangible decision that you will experience every day in the way that you lift and carry and push it (I highly recommend the City Mini). Moral development is largely intangible, gradual and unmeasurable, at least in the early stages of life.
That said, moral development can be witnessed here and there. My daughter experiences real empathy, which she exhibits when she asks why someone is crying in the park or when she pretends to take care of her stuffed flamingo who has a tummy ache. Even my 1-year-old shows empathy: When his sister is crying, for whatever reason, he starts crying, too. It's aggravating as anything in the moment, but he's learning from her what elicits an emotional response, and after the fact, it's kind of amazing.
While this recent piece from the New York Times, "Raising a Moral Child," says that "parents who valued kindness and compassion frequently failed to raise children who shared those values," it also cites specific strategies to help children learn how to be caring. For example, while describing some new research, the author suggests that praising a child's character can help internalize being generous as part of his or her identity.
How we interact with our kids may highlight the kinds of qualities and traits we want to encourage. I think the Jewish view on that is that Judaism has, inherent in its structure, obligations to help people and exhibit kindness. That doesn't mean every kid will act this way all the time, but it does mean that Jewish traditions provide real opportunities to model compassion. Give tzedekah, visit people who are sick, bring meals to families in mourning, greet homeless people with friendliness. These actions won't prevent your kids from taking another kid's toy on the playground, but in the long run, they'll have a better shot at seeing themselves as part of an interwoven community of people who take care of each other.
Be well, and b'sha'ah tova,