Scientist career and "Read to child for 2 hours" requirement

[oshizu]

The baby of a male sim in the Scientist career (Level 5) recently aged up so I tried to do the "Read with a child for 2 hours" requirement.
When I click the children's book, I see three options:
Read [book title]   (with the Scientist's lightbulb breakthrough icon)
Put away (if the book is out) or Place in the world (if in the bookcase)
Put in inventory

In another save, I noticed that the lightbulb icon vanished for certain activities at higher Breakthrough levels.
(For example, at some point, the lightbulb icon didn't appear with "Water" or "Weed" plants.)
Would anyone know if this is also true for the Read to child requirement?

[ClayMask]

I'm a little confused by your post.  Are you saying that the read to child option wasn't listed, and wondered if the command had gone away because you had a lot of breakthroughs?

I can explain why the light bulb is sometimes there and sometimes not for normal activities you see it on, like watering.  Your Sim is only eligible for a certain number of breakthroughs per promotion.  Once your Sim has had the required number of breakthroughs to earn the next promotion, they can't have any more, and the light bulb icon is gone.  It comes back after the next promotion.

[Playalot]

I've just had my scientist dad read for two hours to his child. I put the book in his inventory first and then just chose the option "read to"... (or read with..." can't exactly remember!) and a screen came up so I clicked on the child's picture.

[oshizu]

Sorry for not being clearer. When the scientist clicks on a book, no "Read to..." option appears.

@ClayMask, I think you're right about the number of possible breakthroughs being capped per promotion level.
My level 5 scientist has reached the max 10 breakthroughs for level 5.
The various activities that used to display the lightbulb icon no longer show that icon.
Thank you for pointing out that the game is not letting me make any more breakthroughs until I get another promotion.

@Playalot, I appreciate your confirming that your scientist has access to the Read to [child] option.
The sim will be promoted on his next day of work, so I'll check again whether the lightbulb icon and Read to child option reappear.

Thank you for your responses. I feel a little silly that I wasn't more patient...

[Playalot]

@oshizu, are you placing the book into his inventory first? I don't think the option to read with a child came up for my scientist until the book was in his inventory. 
Either way, I know what you mean about the light bulb disappearing etc. While my sim was gardening it kept appearing and disappearing but eventually he had a break through... I just left him gardening and I guess that each time it appears it fills up a little towards that break through moment.
Yet at other times it has appeared and stayed constantly through the action (gardening) until the break through happened. It is a bit confusing for sure.

[oshizu]

Yay, the sim daddy got a promotion to Ufologist (level 6) and just got back home.
When he opened the bookcase and clicked on a child's book, the Read to.... option reappeared!!!

So I'm confirming ClayMask's point about the lightbulb icon preceding specific activities (weed, water, tinker, observe sky, etc) disappearing once you max breakthroughs for your current Scientist level.  It reappears after the next promotion.

@Playalot, by "lightbulb icon," i mean the little lightbulb image that appears when you click on objects that may possibly lead to a breakthrough.
For example, when you click on a plant, you'll see a little lightbulb icon preceding the options Water and Weed.

I'm unclear how (or why) the availability of the lightbulb icon is related to the "Read to child" requirement, but thank you both for explaining the mechanics related to breakthroughs and career level.
Now the scientist daddy can proceed to complete his Big Happy Family aspiration in my experimental save file.
Much appreciated!