What are some bad things about dating a guy who had a child with another female?

Eyes Wide Open. I will assume this guy plans to be involved in the child's life. If you are looking for a long term relationship with this man, get ready for some complicated family dynamics. If you marry this man you would be the step-mother. Step-parents carry much responsibility and little authority when it comes to parenting a step-child. Think hard and make sure you understand your commitment well.
It depends. Depends on the nature of their relationship. Possibly, they could have been in a loving, committed relationship. It is possible that the female got pregnant without his agreeing to it. A bad thing - is a financial and family obligation elsewhere. However, with love and communication, this can be worked out within the dating relationship. A red flag - was he responsible in relationsh.