Is Gendry Cercei's secret son?
The young blacksmith Gendry, king Robert Baratheon's bastard son might seem to be a less important character in the series, but ever since he'd appeared as having some connection to a royal house, a plethora of theories were suggested about his possible character twist. Many GoT fans have been discussing the possibility of Gendry being not simply the Usurper's bastard son, but a legitimate heir of Robert born from Cercei. And the series provided us with some possible hints to that.
In season 1’s “The Kingsroad,” Cersei visits Catelyn Stark during Catelyn’s vigil at the bedside of her son, Brandon, whom Jaime had attempted to murder. She offers her sympathies to Catelyn and speaks of her first born son, a “black-haired beauty” who died shortly after birth.
To start, Cersei mentions that the baby looked like Robert. The teenaged Gendry we meet also looks like Robert — when Ned Stark meets him in “Cripples, Bastards, and Broken Things,” he immediately deduces that Gendry is Robert’s son. (The same thing happens when Stannis meets him in “Second Sons.”)
Cersei also recalls that she never visited her lost child in his crypt, which seems odd given what a passionate mother she is. Also, Cersei never mentions the child’s name. Could this have been a deliberate move on the part of the writers to keep his identity a secret?
One of Cersei´s main traits is her love for their children.
There is a non-zero chance Cersei was angry when she noticed she was carrying Robert´s son and her first plan was to drink the abortion potion(according to the books).
But maybe she couldn't do it and her maternal feelings could have prevented her from killing her own son in her womb after all.
If this is the case , she would have gotten rid of the baby after giving birth.
In order to support this theory, I remember that according to Gendry´s master he received the baby from a noble knight.
This does not fit Robert´s behavior . He has at least 16 sons and daughters, and doesn't give much support, attention or even tries to hide them. He simply doesn’t care.
And if he does not care, he would not bother himself to make a plan to secretly give his bastard son away. Why did he not do the same with his other 15 bastard sons? So if it was not Robert who ordered some knight to secretly give his son to the blacksmith, so it was the mother. And the mother is not any woman, but a noble one, since it has the power to command knights.
Maybe Cersei disguised her pregnancy and secretly gave birth to Robert´s son, maybe she had conflicted feelings and she somehow loved the baby, despite being Robert's,who she despised, and instead of killing, gave him to adoption with some good prospect to the future (being trained by King’s Landing’s best blacksmith)
Besides, in TV show Gendry himself told Arya that he doesn't remember much about his mother, but that she had blond hair. Also, when asked by Ned about his mother, Gendry says he doesn't remember much about her, except that she was a tavern worker and that she had yellow hair. And from the books we get to know that Cercei would frequently dress up like common folk to sneak out the Red Keep into the city to secretly meet with her twin lover Jaime. Anyway, very soon we'll find out if this theory was true.
Ruben of House Tyrell