If a child gifts their stocks or stock options to their parents, the parents would be responsible for paying any taxes on the gifted assets, not the child.
The key points are:
When stocks or other assets are gifted, the tax liability on any prior gains transfers to the recipient of the gift.
So if a child gifts their appreciated stocks or stock options to their parents, the parents would owe capital gains taxes on the gains when they eventually sell the assets, not the child.
The child does not incur any tax liability from gifting the stocks to their parents. The only potential tax implication for the child is if the assets were generating investment income above a certain threshold, which could trigger the "kiddie tax" to be paid by the parents.
To avoid potential gift tax issues, the parents could utilize the annual gift tax exclusion ($16,000 per parent per recipient in 2023) to gradually transfer the assets to the child over multiple years.
In summary, the parents, as the recipients of the gifted stocks or options, would be responsible for paying any applicable taxes when they sell the assets, not the child who originally owned them.