Sprightly yellow seems to be the hue of choice for corporate wellness chains designing a logo to attract health-minded women. There is the cleansing grapefruit of SoulCycle, the happy buttercup of Drybar. And last year vans started materializing at busy pedestrian spots in Manhattan and Los Angeles that sported the shade of sunflowers. These vans are mobile fertility clinics, inviting women to pop in and learn how to safeguard their reproductive germ line by freezing their eggs. “Own your future,” the ads on the side promise. “Your fertility, understood.”