Hi we have a console app we've written which lets us migrate umbraco content as part of our migration strategy.

If we try and add a DocType to be a child of another DocType it won't inherit any of its parent's properties.

Code:

public int AddDocType(int? parentDocTypeId, string name, string docTypeAlias, IEnumerable<PropertyTypeGrouping> propertyGroupings, IEnumerable<string> childDocTypeAliases, string thumbnail = UmbracoThumbnails.Doc, string icon = UmbracoIcons.Doc, string[] templateAliases = null)
        {
            var contentTypeService = ServiceContext.ContentTypeService;
            var docTypeToAdd = parentDocTypeId.HasValue ? new ContentType(parentDocTypeId.Value) : new ContentType(-1);
            docTypeToAdd.Name = name;

            docTypeToAdd.Alias = docTypeAlias;
            docTypeToAdd.Thumbnail = thumbnail;
            docTypeToAdd.Icon = icon;
            if (templateAliases != null && templateAliases.Any())
            {
                var templates = GetTemplates(templateAliases);
                docTypeToAdd.AllowedTemplates = templates;
                docTypeToAdd.SetDefaultTemplate(templates[0]);
            }
            contentTypeService.Save(docTypeToAdd);

            if(propertyGroupings != null && propertyGroupings.Any())
            { 
                AddTabsToDocType(docTypeToAdd, propertyGroupings.Select(p => p.Name));
                AddPropertiesFromGroupings(docTypeToAdd, propertyGroupings);
            }

            if (childDocTypeAliases != null && childDocTypeAliases.Any())
            {
                foreach (var childDocTypeAlias in childDocTypeAliases)
                {
                    AllowNodeToCreateChildOfType(docTypeToAdd, childDocTypeAlias, false);
                }

                contentTypeService.Save(docTypeToAdd);
            }
            return docTypeToAdd.Id;
        }