The present-value cost of having a child may be at least $300K (measured in US dollars as of roughly 2012) when both direct expenditures and opportunity costs are considered. This shows the value of using the most effective birth-control methods, like the implant and vasectomy. That said, some people may find having children very important to their wellbeing, and in such cases, having children may be worth the cost.
Also relevant: The Cost of Kids: