How to change traits for children

[Frog]

I have twins. One supposed to be an astronaut and the other a surgeon.

The traits I chose with the astronaut are brave, athletic and ambitious. (Handy wasn't an option.)
The one who goes for surgeon I took bookworm, genius and light-sleeper.

It seemed logical to choose light-sleeper because doctors wake up at nights but now I don't know.
I believe I chose wrong because with the character who is supposed to be a surgeon, the lifetime wish that appeared is journalism instead of surgeon.

So how do I change their traits to fix that?
Also, what are the activities as a child I should do to get the right lifetime wish?

[Pam]

Welcome to our Forum.

Since you only mention three traits, it sounds like your twins are still children and that one of them got a wish to be a Journalist.  When they are children, you don't have to accept the wishes for their Lifetime Wish.  If the one you want doesn't pop up during childhood or the teen years, you will be able to choose it when your Sim becomes a Young Adult.  At that point, you'll get to choose from all of the Lifetime Wishes, no matter what their traits are. 

For your Astronaut, the Handy trait will become available at the Teen stage.  Not all traits are available in the younger stages, but they show up later when your Sim has birthdays.

For your Surgeon, Light Sleeper probably isn't a great choice.  All it does it make them wake up during the night for no apparent reason and you have to send them back to bed.  Workaholic would be a good trait for a Surgeon.  You can change traits using testing cheats as long as you're not playing one of our challenges.  First, press and hold the Shift, Ctrl, and C keys on your keyboard.  The screen will darken a little and you can type on it.  Type "testingcheatsenabled true" without the quote marks and press Enter.  The screen will go back to normal and testing cheats are turned on.  Next, hold down the Shift key and click on the Sim whose traits you wish to change.  An option to Modify Traits will appear.  Click it and make whatever changes you want.  When you're done, do the Shift-Ctrl-C again and type "testingcheatsenabled false" to turn off testing cheats.

I hope this helps.  I'm also moving this over to Miscellaneous Help because I think that's a better place for it. 

[Frog]

Thanks.

Also what are the activities i should do with future astronauts and future surgeons (as a child)?

[Schipperke]

thx.

also what are the activities i should do with future astronauts and future surgeons (as a child) ?

I suggest you take a look at the Guide for information on the various careers.  For the medical career, the only skill requirement is logic, which can be boosted by reading the applicable toddler books and later by playing chess, which Sims can do as children.  The military career requires the athletic and handiness skills, and if memory serves, Sims can't start boosting those skills until their teens.  Although there may be a store item that gives young children a head start on handiness, I'm not sure about that.

[Trip]

The block table that came with the base game gives children a head-start on handiness. Kids can work out using the stereo or the TV, but they don't gain anything from it, as far as I know.

For your kid that got the journalism LTW, was it one of those things that popped up in the wish panel while they were still kids? That usually has no bearing on traits. Just on experiences. I've had children have the World Renowned Surgeon LTW pop up after watching a family member die, in spite of them having no traits that would have a bearing on them wanting to be a doctor. I also had a kid very randomly want to become a journalist, even though his traits had nothing to do with journalism (artistic, neurotic, coward). Genius usually gets the World Renowned Surgeon LTW listed among the five available when the sim ages up to young adult.

[hazelnut]

Light sleeper isn't a bad trait for a surgeon, in fact.  Light and heavy sleepers both have the option to sleep at work, which can be a good way to catch up after a long time on call.  I usually go with heavy sleeper because they can also 'listen' to music while asleep.  It's also useful for astronauts, who have a very long shift when they reach the top of the career.