SitecoreService.GetItem not returning Children/Child Items

Question

The below code is not returning the children's,

var TemplateID = Guid.Parse("{51A26CD4-FCB5-4A3C-8720-2D60F625A678}");           
var _Options = new GetItemByIdOptions(TemplateID)
{
    InferType = true,
    Lazy = Glass.Mapper.LazyLoading.Enabled
};
var target = context.SitecoreService.GetItem<IGlassModel>(_Options);

Below is the Model :

[SitecoreType(TemplateId = "{19CDADF8-D474-42C9-8C8D-522A7FF93663}", AutoMap=true)]
    public class IGlassModel
    {
        Guid Id { get; set; }

        string Path { get; set; }

        //[SitecoreItem]
        //string Name { get; set; }

        [SitecoreChildren]
        IEnumerable<Country> Chlidren { get; set; }

    }       

    [SitecoreType(TemplateId = "{780F8593-3AFA-4DF0-98EE-16FFDD18F88F}", AutoMap = true)]
    public class Country
    {
        Guid Id { get; set; }

        string Path { get; set; }

        [SitecoreItem]
        string CountryName { get; set; }

        [SitecoreItem]
        string CountryCode { get; set; }
    }

Answer 1

We faced the same issue any adding virtual keyword worked for us as @Marek is saying in comments as well.

[SitecoreChildren]
public virtual IEnumerable<Country> Chlidren { get; set; } 

Glass mapper document states - One important thing to remember when writing class with Glass.Mapper is to ensure that all your fields are marked as virtual. Glass.Mapper can automatically infer what data to load for your model by using a combination of On Demand mapping and Auto-Mapping.

You can refer blog that is explaining why all Glass mapper field should be virtual - https://stackoverflow.com/questions/33105212/why-should-all-glass-mapper-fields-be-virtual