How long is pregnancy in Fallout Shelter?
Fallout Shelter pregnancies last three hours, and children take another three hours to become adults. Children don't require any care and pregnant dwellers can get right back to work after delivery. If only childbearing were this simple in real life.
Pregnancies last for three hours, and it takes three additional hours for the child to become an adult.
Wait 3 hours.
After a dweller becomes pregnant, you'll need to wait for 3 hours before she'll deliver the baby. Although pregnant dwellers can still work, you'll need to assign 1-2 male dwellers to work with them.
Pregnant dwellers will give birth after a few hours if they are happy and there is enough space in the Vault. If there is not enough room, either upgrade or build additional Living Quarters.
"Super" Child Formula
Parents' total SPECIAL must be 122 or higher to have a chance at a rare child. Two fully maxed out parents (SPECIAL 140) will have a ~6.6% chance of producing a legendary child, and a ~13.3% chance of producing a rare child. Two maxed parents will produce a child with an Intelligence proficiency.
Yes. Despite being a key game-play mechanic, Fallout Shelter does not do much to prevent you manually changing the clock to exploit timers. This should apply to a pregnancy timer; However, this exploit is most popular as a means to rush the production timers, or to farm loot/caps from the wasteland.
Your vault will not suffer from fires, raider/deathclaws/molerat/rad roach attacks, or other events while the app is shut down. Events should still queue up for explorers, unless your guys hit the same crazy survival bug that mine did. The safer thing is to recall them.
How to Get Unlimited Caps & Speed up Time in Fallout Shelter (2021)
Typically you will get someone every 6 to 12 hours guaranteed. If you are trying to max out your dweller capacity you can always do the time method. In case you are unaware of the time method I will explain, if you manipulate the time on your computer can 1) collect resources faster and 2) collect new dweller faster.
Once you've heard the sound effect though, you'll have roughly 7-10 seconds to locate him within your vault, if you failed to find him you'll hear another piano tone play and he'll disappear. Fear not though, he tends to re-appear every few minutes.
Do pregnant dwellers have to be in living quarters?
Pregnancy: While women are pregnant they can work. But they will not take care of any incidents but run into the living quarters instead. Make sure to assign at least one male/non-pregnant Dweller to all stations and don't equip pregnant women with weapons since they don't use them.
The Mysterious Stranger is one of the surprise characters in Fallout Shelter. It randomly shows up at any vault at any time. Ultimately, catching him will give you a few thousand caps. If you are not quick enough, you will miss the chance to get rewards with so much ease.

Afair in the first versions of Fallout Shelter it was possible to inbreed but with some later patch they forbid it which means brother, sisters can't have chieldrens. But thats not really a problem. If you want more dwellers just put them all together, thats it. There's also no point in breeding high stats dweller.
You can't mate full- or half-siblings - if a pair of dwellers shares even one parent, they will not mate. You can't mate parents to their children. You CAN mate grandparents to grandchildren, aunts/uncles to nieces/nephews, cousins to cousins, etc.
Fallout Shelter: How to get Legendary Babies - YouTube
The longest I've allowed a Dweller to explore the Wasteland is 12 hours and they're still only finding BB Guns and other useless junk. So, how do you usually equip your explorers, how many do you send out at once, how long do you let them roam the Wastes, and what are their stats?
Yes, it is possible!!
The following is based on information from Fallout Shelter or Fallout Shelter Online. Rushing is a mechanic found in Fallout Shelter. It can be done at anytime to speed up the production of a room. However, there is always a chance to fail, which will trigger an incident.
At 200 dwellers:
Radio station and dwellers stop showing up unless you find one in a lunchbox, it will stay outside until you kill someone so he/she can go in, or stay outside forever.
No, you do not need to have a dweller in a Storage Room.
Do vault numbers matter in Fallout Shelter?
No, it's just a way to distinguish different vaults you have aside from saveslot number.
Objectives in Fallout Shelter are a means of earning bottle caps and, importantly, also the only way to get Lunchboxes for free. Located under the ribbon symbol in the bottom-right menu on your screen, three Objectives appear at a time, and automatically renew when completed.
Also worth noting is the fact that pregnant Dwellers can continue work in their rooms as normal, and can be equipped with both outfits and weapons, but can't fight or tend to disasters.
Luck also affects the chance of rush attempts succeeding. In the wasteland, it increases the chances of finding items when dwellers go out on quests and explore locations in the wasteland. The higher the Luck, the better the items. During quest combat, it increases the speed at which the critical hit meter fills.
Legendary dwellers are found randomly through opening lunchboxes. Rare dwellers have a total sum of 29 SPECIAL points, with the exception of 3 preset dwellers. Legendary dwellers have a total sum of 40 SPECIAL points.