diff --git a/PlotLine.Tests/Program.cs b/PlotLine.Tests/Program.cs
index 70f5695..a950b15 100644
--- a/PlotLine.Tests/Program.cs
+++ b/PlotLine.Tests/Program.cs
@@ -64,6 +64,7 @@ var tests = new (string Name, Action Test)[]
     ("Phase 21U extracts mandatory character appearance fixtures", Phase21UExtractsMandatoryCharacterAppearanceFixtures),
     ("Phase 21U enforces alias age semantic and UI reset rules", Phase21UEnforcesAliasAgeSemanticAndUiResetRules),
     ("Story Intelligence visual polish keeps labels fixed and semantics specific", StoryIntelligenceVisualPolishKeepsLabelsFixedAndSemanticsSpecific),
+    ("Character sex hints are conservative and reviewable", CharacterSexHintsAreConservativeAndReviewable),
     ("Scan review aliases feed Story Intelligence known character context", ScanReviewAliasesFeedStoryIntelligenceKnownCharacterContext),
     ("Scan review post supports full-book form submissions", ScanReviewPostSupportsFullBookFormSubmissions),
     ("Story Intelligence experience boot does not serialise live model", StoryIntelligenceExperienceBootDoesNotSerialiseLiveModel),
@@ -841,6 +842,14 @@ static void ScanReviewPostSupportsFullBookFormSubmissions()
     Assert(((IRequestSizeLimitMetadata?)requestSize)?.MaxRequestBodySize >= 25 * 1024 * 1024, "Scan review request size limit should support full-book previews.");
 }
 
+static void CharacterSexHintsAreConservativeAndReviewable()
+{
+    Assert(CharacterSexHintService.Suggest("Cindy") == CharacterSexHintService.Female, "Cindy should default to a female sex hint.");
+    Assert(CharacterSexHintService.Suggest("Kevin") == CharacterSexHintService.Male, "Kevin should default to a male sex hint.");
+    Assert(CharacterSexHintService.Suggest("Alex") == CharacterSexHintService.Unknown, "Ambiguous names should not be guessed.");
+    Assert(CharacterSexHintService.Normalise("Female", "Alex") == CharacterSexHintService.Female, "Reviewed sex hints should override the name heuristic.");
+}
+
 static void StoryIntelligenceExperienceBootDoesNotSerialiseLiveModel()
 {
     var view = File.ReadAllText(Path.Combine(AppContext.BaseDirectory, "../../../../PlotLine/Views/Development/StoryIntelligenceExperience.cshtml"));
@@ -1153,6 +1162,8 @@ static void Phase21UEnforcesAliasAgeSemanticAndUiResetRules()
     Assert(onboarding.Contains("<select class=\"form-select\" name=\"primaryAgeGroup\"", StringComparison.Ordinal), "Primary age group must be a dropdown.");
     Assert(onboarding.Contains("<select class=\"form-select\" name=\"storyEra\"", StringComparison.Ordinal), "Story era must be a dropdown.");
     Assert(onboarding.Contains("<select class=\"form-select\" name=\"storyLocation\"", StringComparison.Ordinal), "Story location must be a dropdown.");
+    var scanReview = File.ReadAllText(Path.Combine(root, "Views/Onboarding/ScanReview.cshtml"));
+    Assert(scanReview.Contains(".SexHint", StringComparison.Ordinal) && scanReview.Contains("Non-binary / other", StringComparison.Ordinal), "Character review must expose an editable sex hint dropdown.");
     Assert(storyMemory.Contains("CharacterAppearanceExtractionService.Extract", StringComparison.Ordinal), "Durable Story Memory must consume dedicated appearance extraction.");
     Assert(storyMemory.Contains("SkinToneInstruction(skinTone)", StringComparison.Ordinal), "Demand generation must use hard skin-tone wording.");
     Assert(storyMemory.Contains("HairColours.Red", StringComparison.Ordinal) && storyMemory.Contains("SkinTones.Light", StringComparison.Ordinal), "Red-hair demand evidence must force light skin when skin is otherwise unknown.");
@@ -1283,10 +1294,10 @@ static void ScanReviewAliasesFeedStoryIntelligenceKnownCharacterContext()
     {
         Characters =
         [
-            new() { TemporaryCharacterKey = "c-maggie", Include = true, Name = "Maggie", Category = "ProbableCharacter", ExistingCharacterID = 123 },
+            new() { TemporaryCharacterKey = "c-maggie", Include = true, Name = "Maggie", Category = "ProbableCharacter", ExistingCharacterID = 123, SexHint = CharacterSexHintService.Female },
             new() { TemporaryCharacterKey = "c-margaret", Include = true, Name = "Margaret", Category = "ProbableCharacter", AliasTargetTemporaryCharacterKey = "c-maggie" },
             new() { TemporaryCharacterKey = "c-mags", Include = true, Name = "Mags", Category = "PossibleCharacter", AliasTargetTemporaryCharacterKey = "c-maggie" },
-            new() { TemporaryCharacterKey = "c-kevin", Include = true, Name = "Kevin", Category = "ProbableCharacter" },
+            new() { TemporaryCharacterKey = "c-kevin", Include = true, Name = "Kevin", Category = "ProbableCharacter", SexHint = CharacterSexHintService.Male },
             new() { TemporaryCharacterKey = "c-road", Include = true, Name = "Road", Category = "Excluded" }
         ]
     };
@@ -1297,10 +1308,12 @@ static void ScanReviewAliasesFeedStoryIntelligenceKnownCharacterContext()
     var context = JsonSerializer.Deserialize<List<StoryIntelligenceKnownCharacterContext>>(json!, new JsonSerializerOptions { PropertyNameCaseInsensitive = true })!;
     var maggie = context.Single(item => item.CanonicalName == "Maggie");
     Assert(maggie.ExistingCharacterID == 123, "Existing character ID should stay on the canonical scan character.");
+    Assert(maggie.SexHint == CharacterSexHintService.Female, "Known character context should preserve the reviewed sex hint.");
     Assert(maggie.Aliases.Contains("Margaret"), "Alias target should include Margaret.");
     Assert(maggie.Aliases.Contains("Mags"), "Alias target should include Mags.");
     Assert(maggie.MentionCount == 13, $"Alias mention counts should accumulate, got {maggie.MentionCount}.");
     Assert(context.Any(item => item.CanonicalName == "Kevin"), "Other included canonical candidates should remain available.");
+    Assert(context.Single(item => item.CanonicalName == "Kevin").SexHint == CharacterSexHintService.Male, "Male reviewed sex hints should be preserved.");
     Assert(!context.Any(item => item.CanonicalName == "Margaret"), "Alias candidates should not become separate canonical context records.");
     Assert(!context.Any(item => item.CanonicalName == "Road"), "Excluded scan candidates should not guide Story Intelligence.");
 }
diff --git a/PlotLine/Models/ManuscriptScanModels.cs b/PlotLine/Models/ManuscriptScanModels.cs
index 6d64645..1d5905a 100644
--- a/PlotLine/Models/ManuscriptScanModels.cs
+++ b/PlotLine/Models/ManuscriptScanModels.cs
@@ -154,6 +154,7 @@ public sealed class ManuscriptScanCharacterReviewDecision
     public string Category { get; init; } = "PossibleCharacter";
     public int? ExistingCharacterID { get; init; }
     public string? AliasTargetTemporaryCharacterKey { get; init; }
+    public string? SexHint { get; init; }
 }
 
 public sealed class OnboardingManuscriptBuildResult
diff --git a/PlotLine/Models/StoryIntelligencePersistenceModels.cs b/PlotLine/Models/StoryIntelligencePersistenceModels.cs
index fc8115a..ed98f20 100644
--- a/PlotLine/Models/StoryIntelligencePersistenceModels.cs
+++ b/PlotLine/Models/StoryIntelligencePersistenceModels.cs
@@ -156,6 +156,7 @@ public sealed class StoryIntelligenceKnownCharacterContext
 {
     public string CanonicalName { get; init; } = string.Empty;
     public IReadOnlyList<string> Aliases { get; init; } = [];
+    public string SexHint { get; init; } = "Unknown";
     public int? ExistingCharacterID { get; init; }
     public IReadOnlyList<string> CandidateKeys { get; init; } = [];
     public int MentionCount { get; init; }
diff --git a/PlotLine/Services/CharacterSexHintService.cs b/PlotLine/Services/CharacterSexHintService.cs
new file mode 100644
index 0000000..9c599ca
--- /dev/null
+++ b/PlotLine/Services/CharacterSexHintService.cs
@@ -0,0 +1,73 @@
+namespace PlotLine.Services;
+
+public static class CharacterSexHintService
+{
+    public const string Unknown = "Unknown";
+    public const string Female = "Female";
+    public const string Male = "Male";
+    public const string NonBinaryOrOther = "NonBinaryOrOther";
+
+    private static readonly HashSet<string> FemaleNames = new(StringComparer.OrdinalIgnoreCase)
+    {
+        "abby", "abigail", "alice", "alison", "allison", "amanda", "amelia", "amy", "angela", "anna", "anne",
+        "beth", "bethany", "carol", "caroline", "catherine", "charlotte", "chloe", "cindy", "claire", "daisy",
+        "diana", "emily", "emma", "eva", "eve", "grace", "hannah", "helen", "isabel", "isabella", "jane",
+        "jessica", "julia", "julie", "kate", "katie", "laura", "lily", "lucy", "maggie", "margaret", "mary",
+        "molly", "nicola", "olivia", "rachel", "rebecca", "rose", "sarah", "sophie", "susan", "victoria",
+        "zoe"
+    };
+
+    private static readonly HashSet<string> MaleNames = new(StringComparer.OrdinalIgnoreCase)
+    {
+        "adam", "alan", "alexander", "andrew", "anthony", "arthur", "ben", "benjamin", "brian", "charles",
+        "chris", "christopher", "daniel", "david", "edward", "george", "harry", "henry", "ian", "jack",
+        "james", "john", "jonathan", "joseph", "kevin", "mark", "matthew", "michael", "nick", "nicolas",
+        "nicholas", "oliver", "paul", "peter", "philip", "richard", "robert", "samuel", "simon", "stephen",
+        "steven", "thomas", "tom", "william"
+    };
+
+    private static readonly HashSet<string> AmbiguousNames = new(StringComparer.OrdinalIgnoreCase)
+    {
+        "alex", "andy", "ashley", "billie", "blair", "bobbie", "casey", "charlie", "drew", "frankie",
+        "jamie", "jessie", "jo", "jordan", "lee", "leslie", "morgan", "pat", "riley", "robyn", "robin",
+        "sam", "sandy", "shannon", "taylor", "terry"
+    };
+
+    public static string Suggest(string? name)
+    {
+        var token = FirstNameToken(name);
+        if (string.IsNullOrWhiteSpace(token) || AmbiguousNames.Contains(token))
+        {
+            return Unknown;
+        }
+
+        if (FemaleNames.Contains(token))
+        {
+            return Female;
+        }
+
+        return MaleNames.Contains(token) ? Male : Unknown;
+    }
+
+    public static string Normalise(string? value, string? fallbackName = null)
+        => value?.Trim() switch
+        {
+            Female => Female,
+            Male => Male,
+            NonBinaryOrOther => NonBinaryOrOther,
+            Unknown => Unknown,
+            _ => Suggest(fallbackName)
+        };
+
+    private static string FirstNameToken(string? name)
+    {
+        var clean = name?.Trim();
+        if (string.IsNullOrWhiteSpace(clean))
+        {
+            return string.Empty;
+        }
+
+        var first = clean.Split(' ', StringSplitOptions.RemoveEmptyEntries).FirstOrDefault() ?? string.Empty;
+        return first.Trim('.', ',', ';', ':', '\'', '"').ToLowerInvariant();
+    }
+}
diff --git a/PlotLine/Services/ManuscriptScanPreviewStore.cs b/PlotLine/Services/ManuscriptScanPreviewStore.cs
index 23de1c8..83365d9 100644
--- a/PlotLine/Services/ManuscriptScanPreviewStore.cs
+++ b/PlotLine/Services/ManuscriptScanPreviewStore.cs
@@ -279,7 +279,8 @@ public sealed class ManuscriptScanPreviewStore : IManuscriptScanPreviewStore
                     TemporaryCharacterKey = candidate.TemporaryCharacterKey,
                     Include = string.Equals(candidate.Category, "ProbableCharacter", StringComparison.OrdinalIgnoreCase),
                     Name = candidate.Name,
-                    Category = candidate.Category
+                    Category = candidate.Category,
+                    SexHint = CharacterSexHintService.Suggest(candidate.Name)
                 })
                 .ToList()
         };
diff --git a/PlotLine/Services/OnboardingService.cs b/PlotLine/Services/OnboardingService.cs
index d15dda0..83ded78 100644
--- a/PlotLine/Services/OnboardingService.cs
+++ b/PlotLine/Services/OnboardingService.cs
@@ -180,7 +180,8 @@ public sealed class OnboardingService(
                     Name = cleanName,
                     Category = item.Category,
                     ExistingCharacterID = matchedExistingId,
-                    AliasTargetTemporaryCharacterKey = aliasTargetKey
+                    AliasTargetTemporaryCharacterKey = aliasTargetKey,
+                    SexHint = CharacterSexHintService.Normalise(item.SexHint, cleanName)
                 };
             })
             .ToList();
@@ -426,7 +427,8 @@ public sealed class OnboardingService(
                     AliasTargetName = !string.IsNullOrWhiteSpace(decision?.AliasTargetTemporaryCharacterKey)
                         && characterReview.TryGetValue(decision.AliasTargetTemporaryCharacterKey, out var targetDecision)
                         ? targetDecision.Name
-                        : null
+                        : null,
+                    SexHint = CharacterSexHintService.Normalise(decision?.SexHint, reviewName)
                 };
             })
             .ToList();
diff --git a/PlotLine/Services/OnboardingStoryIntelligenceService.cs b/PlotLine/Services/OnboardingStoryIntelligenceService.cs
index e8032fb..76043e2 100644
--- a/PlotLine/Services/OnboardingStoryIntelligenceService.cs
+++ b/PlotLine/Services/OnboardingStoryIntelligenceService.cs
@@ -296,11 +296,20 @@ public sealed class OnboardingStoryIntelligenceService(
                 .Select(key => candidates.TryGetValue(key, out var candidate) ? Math.Clamp(candidate.QualityScore / 100m, 0.1m, 1m) : 0.5m)
                 .DefaultIfEmpty(0.5m)
                 .Max();
+            var sexHint = CharacterSexHintService.Normalise(root.SexHint, root.Name);
+            if (string.Equals(sexHint, CharacterSexHintService.Unknown, StringComparison.Ordinal))
+            {
+                sexHint = aliasDecisions
+                    .Select(alias => CharacterSexHintService.Normalise(alias.SexHint, alias.Name))
+                    .FirstOrDefault(value => !string.Equals(value, CharacterSexHintService.Unknown, StringComparison.Ordinal))
+                    ?? CharacterSexHintService.Unknown;
+            }
 
             context.Add(new StoryIntelligenceKnownCharacterContext
             {
                 CanonicalName = root.Name,
                 Aliases = aliases,
+                SexHint = sexHint,
                 ExistingCharacterID = root.ExistingCharacterID,
                 CandidateKeys = allKeys,
                 MentionCount = mentionCount,
diff --git a/PlotLine/ViewModels/OnboardingViewModels.cs b/PlotLine/ViewModels/OnboardingViewModels.cs
index 926db36..1ce58b2 100644
--- a/PlotLine/ViewModels/OnboardingViewModels.cs
+++ b/PlotLine/ViewModels/OnboardingViewModels.cs
@@ -673,6 +673,7 @@ public sealed class ManuscriptScanReviewCharacterViewModel
     public bool IsExistingCharacterMatch => ExistingCharacterID.HasValue;
     public string? AliasTargetTemporaryCharacterKey { get; init; }
     public string? AliasTargetName { get; init; }
+    public string SexHint { get; init; } = "Unknown";
     public bool IsAlias => !string.IsNullOrWhiteSpace(AliasTargetTemporaryCharacterKey);
 }
 
@@ -716,4 +717,5 @@ public sealed class ManuscriptScanCharacterReviewFormItem
     public string Category { get; set; } = "PossibleCharacter";
     public int? ExistingCharacterID { get; set; }
     public string? AliasTargetTemporaryCharacterKey { get; set; }
+    public string? SexHint { get; set; }
 }
diff --git a/PlotLine/Views/Onboarding/ScanReview.cshtml b/PlotLine/Views/Onboarding/ScanReview.cshtml
index 5077605..46dd813 100644
--- a/PlotLine/Views/Onboarding/ScanReview.cshtml
+++ b/PlotLine/Views/Onboarding/ScanReview.cshtml
@@ -276,6 +276,15 @@
                                                 }
                                             </select>
                                         </label>
+                                        <label class="onboarding-review-field">
+                                            Sex
+                                            <select class="form-select" name="Characters[@currentCharacterIndex].SexHint">
+                                                <option value="Unknown" selected="@(string.Equals(candidate.SexHint, CharacterSexHintService.Unknown, StringComparison.Ordinal))">Unknown</option>
+                                                <option value="Female" selected="@(string.Equals(candidate.SexHint, CharacterSexHintService.Female, StringComparison.Ordinal))">Female</option>
+                                                <option value="Male" selected="@(string.Equals(candidate.SexHint, CharacterSexHintService.Male, StringComparison.Ordinal))">Male</option>
+                                                <option value="NonBinaryOrOther" selected="@(string.Equals(candidate.SexHint, CharacterSexHintService.NonBinaryOrOther, StringComparison.Ordinal))">Non-binary / other</option>
+                                            </select>
+                                        </label>
                                         <span>@candidate.MentionCount mention@(candidate.MentionCount == 1 ? string.Empty : "s") / score @candidate.QualityScore</span>
                                         @if (!string.IsNullOrWhiteSpace(candidate.AliasTargetName))
                                         {
@@ -311,6 +320,7 @@
                         {
                             <input type="hidden" name="Characters[@hiddenCharacterIndex].AliasTargetTemporaryCharacterKey" value="@candidate.AliasTargetTemporaryCharacterKey" />
                         }
+                        <input type="hidden" name="Characters[@hiddenCharacterIndex].SexHint" value="@candidate.SexHint" />
                     </div>
                 }
             </aside>