Airlines are not allowed to discriminate on family life. They are not allowed to ask you in the interview if you have children, nor do they have to allow for them other than the EU directives over parental leave.
You can be fairly certain that some of your interviewers will be parents and have been crew or are current crew. There is no airline that favours singles over parents (or vice versa) because that would be illegal. Don't go in expecting special treatment and you will be fine.