In Chapter 21 of To Sir With Love, when Gillian's father asks the above question, he expresses the concern that the children will not fit in anywhere and "nobody will want them," meaning that they will not identify with either black people or white people. Having heard this remark before, Mr. Braithwaite is irritated by the question. At first, he replies that his and Gillian's children will not be anyone's business but their own. Then, his ire is raised some, for he tells Mr. Blanchard that he need not worry about Gillian and him; they will test the fates, even while realizing the compromising situation that Mr. and Mrs. Blanchard will be in to have "colored grandchildren"
"...I don't suppose you were able to offer Mrs. Blanchard any guarantees that her children would be strong, healthy, or without physical deformity. We, too, will take our chances, though I appreciate how very inconvenient it will be for you to have colored grandchildren."
At this rather caustic retort, Mr. Blanchard holds out his hand to silence Rick, saying, "No need to become too heated, young man, you have made your point." He then explains that he raised these questions because other people certainly will; Mr. Blanchard wants Rick to understand the difficult position he and Gillian will find themselves. With this final comment, Mr. Blanchard offers Rick his hand.