Recommend some drama with happy ending where male leads are shown with kid at the end with a happy family like following :

1) She was Pretty 

2) Strong Woman Do Bong Soon 

3) Fated to Love You 

4) Secret Garden 

5) Princess Hours

6) The Mask

7) Reply 1997

8) The Universe's Star

9) Legend of the Blue Sea

10) Oh my Venus 

11) It's ok That's Love


https://mydramalist.com/81-autumns-concerto  ---> don't have to wait till the end for the kid to appear :D

Autumn's Concerto

Bride of the Century

Stars Falling From the Sky- the drama finishes with them finding a baby on their doorstep and deciding to adopt it.

Sweet 18

Ugly Alert

Down with Love 

Lady & Liar

The Taiwanese version of Fated to Love You- She delivers the baby in the last episode, you can see them as a happy family in the drama Woody Sambo (which also ends with them having a child), the shows are connected and the characters from Fated to Love you make a cameo in one of the first episodes with the baby.

The Greatest Love

Jealousy Incarnate

My Little Baby

The greatest love

The Moon embracing the sun

Long Dramas:

- Smile, You

- Jewel in the Palace

- Dong Yi

-  Hotel King


Short/ Normal lenght Drama:

- Bride of the Century

- The greatest Love

 



Go back couple
18 again
Flower of Evil
Welcome 2 Life
The King 2 Hearts
Familiar Wife

What about five kids? One of the best family dramas, Five Children a.k.a. Five Enough.
Sorry I'm not allowed to post links yet, it gives me an error message. 

Princess hours

melting me softly

Princess hours doesn’t have ha kids in the end

My understanding of the OP question is that the relationship results in kids, not that there are kids in the series from beginning like in some of the above mentioned series (18 again).

I also wonder if the FL being pregnant at the end also qualifies. (I think so too)

Sweet 18   
Hana Yori Dango    (japanese)
Mr. Queen   
Moon Lovers: Scarlet Heart Ryeo