Beeing Female NG vs. Fertility Mode Reloaded¶
Beeing Female and Fertility Mode are the two best-known female reproductive-cycle / pregnancy frameworks for Skyrim. They cover the same broad ground — menstrual cycle, conception, pregnancy, birth, and born children for the player and NPCs — but they're built on different foundations, with different design priorities.
This page is a neutral, technical comparison of the two current, actively-maintained versions: Beeing Female NG (this project) and Fertility Mode Reloaded (FMR). It focuses on what each does today — architecture, features, requirements — not their origins. Architecture and feature claims are drawn from the Papyrus/C++ sources both ship; hosting and requirements are cited from public pages. Specific version references are BF NG 3.5.x and FMR 1.0.3 — both mods evolve, so re-check current pages before deciding.
Why this page exists
People routinely ask which of the two to run, or whether they can coexist. They generally should not run together — both track the same NPCs and apply belly scaling, so they fight over the same state. Pick one. This page lays out the trade-offs honestly, including where the other mod is the better fit.
At a glance¶
| Beeing Female NG | Fertility Mode Reloaded | |
|---|---|---|
| Foundation | Hybrid SKSE C++ plugin (CommonLibSSE-NG) + Papyrus | Papyrus, built on JContainers + PO3 |
| Hosting | Nexus · GitHub (GPL-3.0) | Nexus |
| Platforms | Skyrim SE / AE / VR | Skyrim SE / AE / VR |
| Status | Actively maintained | Actively maintained |
| Core philosophy | Deep simulation + broad features, with active performance engineering (distributed ticking, idle cleanup, load-gating) | Leaner and bounded by design (hard cap, batched throttles) |
Architecture & performance¶
This is the deepest difference between the two, and it shapes everything else. The two mods take opposite approaches to ticking the cycle.
The loop¶
Beeing Female NG — decentralized, per-actor. Each tracked female carries an ability (BeeingFemaleSpell) whose effect script is her cycle state machine. She ticks herself via a self-rescheduling game-time update; the interval changes per state (≈1 game-day for most phases, 0.2 day during labor). There is no central loop iterating every woman. Discovery is a magic-effect "cloak" that tags nearby valid actors.
Fertility Mode Reloaded — centralized, single loop. One quest-alias script ticks on a fixed game-time interval (default 1 hour, MCM 1–24h) and then iterates the entire tracked array, updating each woman in one pass. Discovery is event-driven through powerofthree's Papyrus Extender (RegisterForObjectLoaded), so there is no cell scan.
| Aspect | BF NG | FMR |
|---|---|---|
| Tick model | Per-actor self-scheduling magic effect | One central loop over an array |
| Interval | Dynamic per state (1 day / 0.2 labor) | Fixed (default 1 game-hour) |
| Discovery | Cloak magic effect | PO3 RegisterForObjectLoaded (no cell scan) |
| State storage | Explicit states 0–8 persisted (StorageUtil) | Derived from timestamps each tick |
| Tracked-actor cap | Soft — bounded by idle cleanup | Hard cap 256 |
Discovery — how each mod finds NPCs to track¶
BF NG — cloak magic effect. BF casts a Skyrim cloak spell on the player: a constant ability with an area effect that the engine continuously applies to every actor who comes within range. The first time an actor enters that radius, the cloak's effect script (FWCloaking) runs once for them — it validates the actor (sex, race, uniqueness, and the mod's tracking rules) and, if eligible, adds the cycle ability (BeeingFemaleSpell for women, BeeingMaleSpell for men, plus an items spell for non-unique females when enabled). A dedup list (BF_CloakEffectList) makes sure each actor is processed only once, and once an actor is untracked their marker is cleared so the cloak can re-add them later.
There is a single cloak, on the player only — no cloak runs on NPCs. The appeal: the engine handles proximity for free, with no scan loop or load-event plumbing to maintain. The catch is twofold. First, reach is limited to the player's vicinity: an NPC is discovered only when the player comes within the cloak's radius, so a woman elsewhere in the loaded area isn't tracked until the player gets near her. Second, cloaks have a general overhead reputation — but BF's is deduped (BF_CloakEffectList): a newly-seen actor pays a one-time validation (sex/faction/race checks) the first time, and every re-application after that is a cheap early-out. So the real cost is front-loaded per new actor and concentrated where the player is — a burst when first entering a packed city, near-free walking among already-known NPCs.
FMR — PO3 object-loaded events. FMR instead registers for powerofthree's Papyrus Extender RegisterForObjectLoaded (form type NPC), which fires whenever a relevant actor's 3D loads in. There is no proximity cloak and no cell scan. The catch is that entering a cell loads many actors at once, so the event fires in a burst — a discovery spike at the exact moment of a cell transition, when the engine is already busy streaming in the new area. FMR's answer is the batched queue: incoming actors are buffered and drained only ~10 per 0.1s, spreading that burst across several frames instead of landing it in one. So the spike is mitigated rather than absent, and the approach makes PO3 a hard requirement.
In other words, neither approach is free — they just put the cost in different places. The cloak pays a one-time validation per newly-seen actor (cheap deduped re-checks thereafter), bursting only when the player enters a new crowd; PO3 events pay in a cell-entry burst that has to be batched away. They also differ in reach: the player-only cloak finds women within its radius around the player, while object-loaded events fire for any NPC the game streams into the loaded area. Both mods require PO3 regardless, so this is a difference in discovery mechanism, not in dependencies.
A BF NG plus — couple simulation. Discovery only decides who gets tracked. On top of it, BF NG lets you author relationships: an in-game Couple Widget (hotkey-driven, with optional bulk JSON import) assigns each woman a husband, affairs, and partners. Background auto-insemination then simulates those couples over time — assigned NPCs conceive with their partners even when the player is elsewhere, weighted so a husband is far likelier to be the father than a passing stranger. It turns a flat tracking list into an authored social layer.
Performance trade-offs¶
Neither approach is strictly "faster" — they fail differently under load:
- BF NG spreads cost across many self-scheduled ticks, so there is no single hot loop; it degrades gracefully with very large tracked populations. Tracking is kept in check by idle-NPC untracking — a non-pregnant, idle woman the player hasn't been near for several in-game days is dropped (and re-discovered later), which bounds the population and stops her ticks. Heavy per-actor work (belly morphs, instant-born) is gated on
Is3DLoaded. - FMR pays for one synchronous loop but layers explicit throttles on top: a batched discovery queue (~10 actors per 0.1s), staggered belly rescaling on cell change (a few actors per tick), and milestone-gated mod-events to avoid VM spam. Its safety nets are the 256 cap and a location-based auto-cleanup that drops NPCs the player left ~48 game-hours ago with nothing in progress. Its main cost center is the fertility loop itself, which is unbatched and scales linearly toward the cap.
In short: BF NG distributes work (graceful, soft-capped via idle cleanup); FMR centralizes it (hard-capped, with explicit throttles). Both gate heavy visual work on whether the actor is loaded.
Feature comparison¶
Both cover the core loop; they diverge in breadth and depth.
| Feature | Beeing Female NG | Fertility Mode Reloaded |
|---|---|---|
| Menstrual cycle | ✅ Full 4-phase (follicular/ovulation/luteal/menstruation) | ✅ Cycle-day phases, per-actor offset to desync NPCs |
| Conception | ✅ Sperm decay + fertile-window gates; "any period" overrides | ✅ Dual system (cycle-day + egg-age) to survive fast-travel |
| Contraception | ✅ Items + widget countdown | ✅ Potion + effect clamping fertility |
| Pregnancy scaling | ✅ 5 backends (NiOverride, b3lisario nodes, weight, SLIF) | ✅ NiOverride morphs |
| Miscarriage | ✅ Rich 6-stage system (fever, infection, bleed-out) | ✅ Simpler, player-focused baby-health damage |
| Birth / labor | ✅ Multi-stage (4 phases), water-break, DHLP suspend/resume | ✅ Event-threaded labor with anim + lock |
| Labor pain & expressions | ✅ Graduated pain effects (screen-blur / iMod, per-race & per-actor magnitude) + facial expressions during birth (via SexLab or SexLab-independent) | Labor animation (idle) |
| Born children | ✅ Actors with growth, skill/perk menu, grow-to-adult | ✅ Baby grows into spawned NPC |
| Child race / species | ✅ Vanilla, races from other installed mods, and real creatures as children (via race + creature-child add-ons) | Vanilla races + vampire variants; creature fathers only |
| Child → follower | ✅ Grow-up to adult, summonable, marriage/follower factions | ✅ Class-based training, summonable |
| Baby models & sounds | ✅ Custom carried-baby models (slings, UBE / worn-item add-ons) + baby crying sounds | Baby item at birth (item / soul gem / none) |
| NPC tracking | ✅ Player + NPC; in-game couple-simulation menu (husband/affairs/partners) + auto-insemination | ✅ Player + NPC, creature fathers, unique-only filters |
| PMS effects | ✅ 10 variants | ❌ |
| Menstrual hygiene | ✅ Pads/tampons, soiling, blood FX | ❌ |
| Tattoos | ✅ SlaveTats (semen/womb) | ❌ |
| HUD widgets | ✅ 6 widgets | ✅ Single widget |
| Add-on framework | ✅ INI-driven (race/actor/CME/misc), no scripting | Faction-rank + mod-event hooks |
| Mod-event API | ✅ BeeingFemale* events |
✅ FMR_* events; DAR/OAR faction ranks 0–120 |
Where each pulls ahead:
- BF NG has the broader, deeper surface: hygiene, PMS, a 6-stage miscarriage system, tattoos, five scaling backends, Devious Devices awareness, and an INI add-on framework that lets patchers extend it without editing scripts — including children of races from other installed mods and real creatures as children (creature-child add-ons), driven by per-race/per-actor INI overrides. It's a simulation.
- FMR is the more focused, defensively-engineered mod. Its standout gameplay features are the class-based child-training system and a DAR/OAR faction-rank API that animation add-ons hook directly.
Requirements & integrations¶
| Beeing Female NG | Fertility Mode Reloaded | |
|---|---|---|
| Always required | SKSE64, SkyUI, PapyrusUtil, PO3, Address Library | SKSE64, SkyUI, JContainers, PO3, UIExtensions, Address Library |
| PO3 (Papyrus Extender) | Required — nearby-NPC scans, hit events | Required — discovery, death cleanup |
| Recommended (both) | BodySlide (body morphs) · Papyrus Tweaks NG (script performance) | BodySlide · Papyrus Tweaks NG |
| Data storage | StorageUtil / JsonUtil (PapyrusUtil) | JContainers |
| SexLab | ✅ SLSO, SexLab P+ cum events, hentairim tags, Devious Devices chastity awareness | ✅ SLSO |
| OStim | ✅ player and NPC↔NPC | ✅ player and NPC↔NPC |
| Estrus family | ✅ Defers its cycle to active Estrus Chaurus / Spider / Dwemer pregnancies | ❌ |
| DHLP | ✅ Respects & emits dhlp-Suspend / dhlp-Resume around birth |
❌ |
| Other | Bathing in Skyrim, SlaveTats (optional) | DAR/OAR "Immersive Effects" add-ons |
Which should you run?¶
There is no universal "better." A reasonable way to choose:
- Choose Beeing Female NG if you want the deepest simulation — menstrual hygiene, PMS, detailed miscarriage, tattoos, multiple body-scaling backends, Devious Devices integration, or an INI-driven add-on ecosystem — and you don't mind a larger feature surface.
- Choose Fertility Mode Reloaded if you want a leaner, bounded system with a hard tracked-actor cap, the class-based child-training progression, or tight DAR/OAR animation integration — and you're comfortable with its JContainers + UIExtensions dependency stack.
- Don't run both. They track the same actors and both drive belly scaling; pick one per playthrough.
Sources & further reading¶
- Beeing Female NG: Nexus · GitHub (GPL-3.0) · these docs.
- Fertility Mode Reloaded: Nexus.
- powerofthree's Papyrus Extender: Nexus.
For BF NG specifically, see Getting Started, NPC Pregnancy & Couples, and the author-facing Add-on Framework and StorageUtil & State Data.