Can my father's wife keep his biological children from attending his funeral?

The loss of a loved one, especially an immediate family member, is painful enough without having disputes over the funeral and who can attend. Everyone wants and deserves to pay their last respects and have closure with their loved one. I am sorry you are having to go through this. When family dynamics suggest there may be conflict like this, or just to make sure none arise, it is recommended that everyone have an Advance Directive or other signed and witnessed documents in place that contains specific instructions as to disposition of their body, funeral and service arrangements, and appointment of someone to carry out those wishes. This is provided for under Maryland law. In the absence of such written instructions by the decedent, Maryland Health Occupations Code, Section 7-410, sets forth in order of priority those persons who may make the funeral arrangements, starting with the surviving spouse of the decedent. Funerals are often private affairs, so unless there is a religious ceremony held in a church, synagogue, temple or other place whose activities are open to all, then unfortunately, the spouse can control who attends. It is a horrible person who would deny children the ability to mourn their parent at the funeral and burial, but I do not know the family dynamics. Perhaps disputes and rancor are so bad that the risk of a blow-up at this time of grief among disputing family members is too great. I suggest you make a heatfelt entreaty to his spouse to allow the family access to grieve their father, and to heal whatever wounds exist at this time of sorow rather than inflame them further. I imagine that settling your father's estate will also likely not be a pleasant experience under these circumstances.