Kinsey's studies showed sexuality is fluid. So why not? If you set your mind to it. But it still might not work. There's no guarantees that you will become gay, straight, bisexual, or asexual. Or you might try to become one thing and become another thing entirely. But it might be able to work sometimes for some people. Maybe there is a choicesexual gene.
I believe that people are born the way they are sexually. I also believe that you can decide to be anything that you put your mind to. This means that if you decide to be gay, you can be gay. All you have to do is put in the effort to change.
One can not decide to be gay, straight or undefined. This is build into their DNA, and they do not have a choice. If it were a choice, do you not think that many people who are getting bullied in schools and other areas would not simply choose to be straight.
Most people know that their sexual orientation is not a choice but something that is part of them. However, there are some people, especially older women, who have been in the middle of the spectrum and finally realize that and make the choice to align themselves with other women through dissatisfaction with their male/female relationships.
You can not decide to be gay or straight or undefined. It is definitely not a choice to choose your own sexuality. If you believe that it is then I ask you when did you decide? We do not decide who we are attracted to. We have influence but ultimately you do not decide your sexuality.
One cannot decide whether they are gay or straight. People do not choose what kind of people they are attracted to. It is natural for some people to be gay or straight. People should be more understanding of different lifestyles and they should not hold stereotypes about them because of their preferences.