A frequent question from my undergraduate students is about the value of drinking milk as an adult - and which of the plant-based "milks" might be a good alternative. First, there is not good evidence that moderate cow's milk or dairy consumption as part of an overall healthy diet presents risk - and actually some good evidence of health benefits. However, it is also very possible to have a healthy and adequate diet without cow's milk - just may need to consider alternate sources or supplements for nutrients (like calcium, vitamin D, riboflavin) for which milk is a good source. Here is an excellent article with an overview of cow's milk and milk alternatives by a registered dietitian. My vote for the closest milk alternative is soy.