fallout-shelter
I got an objective to have 15 male and female couples dance. I'm at 9 times now and I've only 2 pregnant women (I only need 2 right now, might ruin it if I get another one).
My question is: if I put a pregnant dweller with a male dweller in the living quarters, will they still dance?
Mating: Bring a male and a female Dweller together into the living quarters. In larger living quarters you can bring in more Dwellers and let them work it out. The higher the Charisma the faster they will mate.
Direct offsprings will not mate, the game prevents incestuous behavior. If you do not keep log of your bloodlines (which you most probably don't) there are two ways to detect blood relationship:
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.
Deliver Baby: After mating it takes 3 hours for a baby to be born. You do not have to be in the game for this whole time. Just come back after 3 hours and you'll have a baby.
Make sure to have enough room in your living quarters. If your vault is full, women will simply stay pregnant until there is free room. There won't be an indicator and neither the pregnant dwellers will complain in any way. (Also see maximum population below)
Growing up: It takes another 3 hours until children are fully grown up. In their stats they have a grow-up-bar. During this time they can not be assigned to jobs. Again you do not have to be in the game during this time.
Overpopulation: Take care to not grow too fast. Once a baby is born you will need to feed it. Since children won't work you quickly run out of resources and have to juggle your workforce between your water treatment plants and diners if you get too many babies at once.
Maximum Population: The maximum number of dwellers in the vault is 200 - if you reach 200 dwellers, you have to be very careful placing men and women together in living quarters, or you'll have a whole lot of perpetually-pregnant females.
Yeah, Fallout Shelter objectives can sometimes be weird or frustrating but depending on the reward you can decide it's worth the trouble or dismiss it (if you haven't dismissed anything else that day).
How I completed several Assign X dwellers to the right room objectives was to send dwellers exploring the wasteland and when they come back you assign them to the right room or retrain a dweller on another skill. If it has 3 S and 2 A, you retrain his Agility and put him in the Diner.
This can take a lot of time but like I said, it all depends on the objective's reward. The second objective: Have 1 Bald Dweller in the Vault can take even more time but you can start by making a lot of kids. You need the people for your Vault anyway... I'm making around 10 people a day. Today, 2 of them were bald. So it's just chance. If you have radios, there's also the chance that a new dweller is bald...
Remember the fact that Fallout Shelter it's not really the type of game were you start and play for hours... there are objectives or actions that can take hours or days in real life so you just adapt to this gameplay. It's a bit like a Tamagotchi :)
Best Answer
Dwellers dance when they are about to make a baby.
Given that pregnant dwellers can not get pregnant, no. Pregnant dwellers will not dance.
I have confirmed this with a GameFAQs forum post, where a user advises on how to complete this objective quickly, and without the issue of having to worry about overpopulation.
TL, DR: As soon as the dwellers start dancing, it counts as them having danced. Immediately move one of the dwellers to a different room, then immediately move them back. The "baby making process" will reset, and you will have made them dance, without getting one of them pregnant.